Monthly Archives: January 2022

Short Answer Type Question:

Q1.Which elements of Greek and Roman culture were revived in the fourteenth and fifteenth centuries?

ANSWER:

The fourteenth and fifteenth century saw a revival of the Greek and Roman cultures. This bygone era of the Greek and Roman cultures is referred to as the era of classicism. Classicism as a philosophical discipline was expressed in literature, arts, music and architecture during the period of Renaissance.

The focus of this classical revivalism was human beings .It advocated the principle of dignity of man as man. Human life was no longer regarded as a halting point for achievement of eternity but as an end in itself.To unearth this philosophy, all lost ancient Latin manuscripts were translated into the language of the masses. Other than literature, Italian artists found inspiration in the old art and sculptures. The use of columns in architecture and bronze casting in sculpture also reflects the revival of classicism.

Q2.Compare the details of Italian architecture of the period with Islamic architecture.

ANSWER:

The Renaissance period saw a renewed interest in classic architectural forms. The Gothic architecture was replaced by elements of the classical Greek forms.  Domes, columns, arches and vaults became prominent in Italian renaissance architecture.  Planar classicism or flat classicism is what most Italian structures of the 15th century depict. The walls of these buildings are ornamented with classical motifs. These walls are also divided into well-defined sections using pilasters, columns or string courses. The most common buildings types constructed in renaissance Italy were urban mansions (palazzo), country mansions (villa) and churches.

Islamic architecture, on the other hand, is mostly visible in the religious buildings such as madrasas and mosques. Islamic architecture is often referred to as the architecture of the veil due its chief characteristic of privacy predominant in all its structures. The most important form of Islamic architecture is the hypostyle mosques. The basic unit of the hypostyle mosque was the bay. The bay is an area covered by four columns. In hypostyle, this bay could be expanded so as to allow the mosque to grow along. This could enable the growing community to find space for prayers.  These mosques had an inner courtyard surrounded by riwaqs or arcades on three sides.  The courtyards usually have a fountain to conduct wudu. Minarets also made their appearance in Mosques in this form. The most famous hypostyle mosque is the Great Mosque of Kairouan, Tunisia.

Q3.Why were Italian towns the first to experience the ideas of humanism?

ANSWER:

The idea of Humanism was a direct off-shoot of the Renaissance spirit. Very similar to the Renaissance, humanism emphasized on breaking the medieval practice of outright reliance on religious teachings to gain holistic knowledge. The ancient Greek and Roman philosophies, literatures and historiographies, according to the humanists, were the best means to establish the long lost tradition of rationality.  Italy had a persistent connection with Rome. Already exposed to the classical tradition of the old civilisation, the launch of humanism in Italy was inevitable.

Apart from Italy’s connection with ancient the Rome and Greece, the commercial revolution in Italian towns provided an important ground for the launch of humanistic thoughts.  The active trading with the Byzantine Empire, China and Western European countries revived several Italian trading towns like Florence and Venice.  Trading activities created a class of people who were rich and educated. The exposure of the emerging class of lawyers and notaries to the ancient Roman civil law opened new spaces for the deeper understanding of Roman institutions. These changes in the lives of Italian population served to better inculcate the spirit of humanism that emphasized on individual accomplishments and not transcendental achievements.

Q4.Compare the Venetian idea of good government with those in contemporary France.

ANSWER:

There lies huge difference between the Venetian and the French governments. The best way to describe the Venetian Government is ‘Venice über alles‘, meaning ‘Venice above all’. This statement proves that Venice had a more just and efficient government as compared to any other European governments in contemporary times. On the other hand, the 15th century French government has been referred as ’Feudal barbarism’ by Napoleon Bonaparte.

The Venetian administration was mostly controlled by the Great Council. It comprised some of the prominent members of the city. The state to these patricians was a mere extension of their family and individual interests.  These people realised that only the efficient administration of the state could ensure the effective functioning of the trading, which was the primary source of revenue of the land.

People of the lesser ranks such as the merchants, doctors and lawyers also had an important role to play in the state. They served as the ambassadors and diplomats. The lower ranks also had important rights and obligations. Thus, the administration of Venice was a participative practice.  The government made all efforts to fulfil the needs of the poor. Provisions were made for the supply of food, conducting great ceremonies and celebrations, and assurance of legal system with justice for all.The French government stood polls apart from the Venetian style of governance. It was based on the system of Feudalism. Feudalism was a social and economic system that existed in France, England and Italy during the 9th and 15th century. Here, the agricultural production was based on the relation between lords and peasants. The lords owned huge lands, and the peasants had to cultivate their own lands as well as the lords’ land. In return for the services rendered by the peasants, the lords provided military protection to them. The lords also extended judicial control over the peasants and the settlement. This practise was highly exploitative. The worst sufferers were the serfs, who were devoid of all rights. The serf had extreme low status in the society. The word of the master was the law. He could not raise a voice against the master. Legal rights also did not exist for either of him.

Q5.What were the features of humanist thought?

ANSWER:

Predominant social philosophy and literary and intellectual currents of the period from 1400 to 1650 is known as humanism. With trade expansions, growth of prosperity and luxury resulting in development in social values and secular attitudes, there was a shift from theocentric to anthropocentric world. The general emancipation of man was focussed upon. Humanism was a restoration of true civilization after the Dark Age that had set in after the fall of the Roman Empire. The main features of humanism are given below.

1. Humanism stressed on the individual skills. A person with many skills and interests have been referred to as the Renaissance man. The emerging belief in individual potential helped to identify a town by its citizens.

2. The Humanist thought had a very different idea of history. According to this thought only humanism could revive the long past true civilisation. This revival would enable to end the Dark Age that Europe was then passing through.

3. The establishment of the New Age would mark an end to the period of the supremacy of the Church. The basis of humanism is naturalism, which is antithetical to the beliefs of Christianity.

4. Humanism revived the classical Greek literature. The works of Aristotle and Plato were translated. Along with these subjects modern faculties such as chemistry, mathematics, natural science and astronomy also became a part of the college curriculum.

5.  Not only formal education but also art, architecture and books were effective mediums of transmitting humanist ideas. Drawing realistic paintings and sculpting perfectly proportioned figures of men and women were expressions of humanism. Painters and sculptors started to rely on anatomy, geometry and physics to recreate reality.

Q6.Write a careful account of how the world appeared different to seventeenth-century Europeans.

ANSWER:

By the end of the 17th century, the world had stepped into the modern age. This was the age of modern and rational thinking, an age that questioned old ideas and beliefs. These new thoughts enabled man to see the world in an entirely different light than what he did before.

The world in the 17th century was very different from the bygone 16th century.  

Evolution of Modern Science and Philosophy

The 17th century has often been referred to as the Age of scientific revolution. Scientific finds of this period changed the way man perceived the world.  The age of scientific revolution moved a step ahead from the preceding age of Enlightenment by explaining the relationship of man with nature.  Men like Rene Descartes (philosopher) and Isaac Newton (mathematician) went ahead the authority of medieval intellectuals such as Galen, Aristotle and Plato.  All available ideas of the medieval age had to pass through the litmus test of ‘doubt’ to be established as the ‘truth.’ This new idea of the ‘truth’ created a world that was very different from what existed earlier. This idea of scepticism was  the determining factor that led to the questioning of the Church’s authority too.

Age of Military Revolution

The 17th century has also been referred to as the period of military revolution of the pre-modern age.  The zeal for colonisation led the Dutch, English, French, Spanish and Portuguese to fight repeated wars in the colonies and in the Europe too. This fostered the spirit for technological military inventions, which could assure an upper hand in the wars.

Thus, the 17th century can be regarded as a big leap, from ignorance to awareness, for the Europeans. The European world was more progressive than in the past century.

Long Answer Type Question:

Q1.Discuss the different scientific aspects reflected in the works of sixteenth century Italian artists.
ANSWER:
Following facts reflect the different scientific aspects in the works of Italian artists:

• Andreas Vesalius (1514-64), a Belgian and a professor of medicine at the university of Padua was the first to dissect human body. This was the beginning of modern physiology. The artists went to the laboratories and studied skeletons there. They started working once they learnt the body structure of human beings.
• Fragments of art discovered from the ruins of Roman Empire, became helpful to the Italian artists as perfectly proportioned men and women were sculpted there. On the basis of this study, one of the sculptors Donatello made life like statues in 1416.
• Leonardo da Vinci was a painter and artist. He painted Mona Lisa and The Last Supper. His self-portrait is vibrant and catchy.
• Scientific taste in arts like sculptures naturally had to emerge life-like vibrancy in the artifacts.

Q2.What were the demerits of the nation-states?
ANSWER:
The nation-states were established in the Renaissance period. These states were governed by a strong political ruler. These states used to keep themselves free from all kinds of interference, i.e. political or religious.
Following were the demerits of the nation-states:

• Attitude of King: The king was the supreme authority. Being despotic, their self-interest was supreme. The Pope and feudal lords could not force them to work in the interests of the state and its people.
• National Interest: States became self-interested and individualistic after the creation of nation-states. International interests were ignored. An environment of animosity also appeared because of the clash of interests of different nation-states.
• Feeling of Selfishness: There developed a feeling of selfishness among the people. This resulted in the feeling of hatred in the minds of people for other nation-states.

Q3.Describe the changes brought by the Renaissance in the contemporary life of the people.
ANSWER:
Renaissance brought the following changes in the contemporary life of the people:

• Old age superstitions and social evils came to an end.
• New ideas and scientific beliefs began to gain much importance.
• It also laid emphasis on humanism.
• People began to discard old values.
• It inspired the contemporary writers and philosophers.
• Many universities were established to provide education.
• Education and knowledge began to spread quickly.

Q4.How did the Italian culture revive after the fall of Western Roman empire?
ANSWER:
There were some changes that took place after the fall of Western Roman empire. These changes revived the culture of Italy. After the fall of Western Roman empire, political and cultural centres in Italy were destroyed. There was no unified government at that time. Italy was a weak and divided country. Pope was sovereign in his own state but not quite strong in European politics. Regions of Western Europe were reshaped by feudal relations. These regions were unified under the Latin church. The Byzantine empire brought changes in Eastern Europe. A common civilization was being created by Islam in the west.
The above-mentioned changes were responsible for bringing about the revival of Italian culture.

Q5.The seventeenth century Europeans witnessed the world as different. Explain. (HOTS)
ANSWER:
Europeans witnessed the world different due to the following reasons.

• A distinct urban culture was developed. People living in towns started thinking as more civilized than rural people.
• Towns started to grow in many European cities.
• Florence, Venice and Rome were the main towns which became centres of art and learning.
• The rich and aristocratic people patronized artists and writers.
• Invention of printing press made books available to many people.
• People began contrasting their modem world with the ancient one of the Greeks and Romans. This was the beginning of the development of a sense of history in Europe.

Q6.What were the causes of Renaissance in Western Europe?
ANSWER:
Following were the main causes of Renaissance in Western Europe:

• The Crusades : Many fanatic lords and barons died during the crusades. Besides this, people came in contact with the developed culture of the Arabs. The new ideas inspired them to think freely. They started learning about the superstitions and narrow mindedness which proved helpful in bringing Renaissance.
• Spread of Islam : During the period of the Middle Ages, Islam spread rapidly. Constantinople was conquered by Turks in 1493.This resulted in the fleeing of most of the Christians from Constantinople to Italy and some other places. They spread among the people the spirit of reasoning and free thinking. All these led to the Renaissance.
• Emergence of cities and towns : Growth of free cities took place due to the decline of feudalism. In these cities, trade, commerce and industry grew quite rapidly. The trading class became rich. They did some welfare works also. They set up many schools and colleges.

Q7.What were the main characteristics of Renaissance?
ANSWER:
The meaning of Renaissance is rebirth. Renaissance resulted in coming out of nation-states out of darkness of medieval ages. Because of Renaissance, these nation-states saw the light of modern era. Men became rational and scientific in their approach. New ideas and style came into prominence.
The main characteristics of Renaissance are as follows:

• Cities of Italy emerged as the first centre of the Renaissance.
• Architecture and literature developed.
• A new style came into prominence.
• New towns came into existence.
• Humanism, free thinking and reasoning emerged.
• Men became rational and scientific in their approach.

Short Answer Type Question:

Q1.Describe the life of Christian monks in a monastery during the medieval period of Europe.
ANSWER:
The men who led the life of self-denial and self-control were called monks. The monks lived in monastery and led the simple life. They had to take a vow not to acquire any kind of worldly possession. They were not allowed to marry and had to take a vow to obey the chief of monastery. Their only mission in life was to pray and preach and to spread moral teachings among the common people.

Q2.What do you understand by manor? Describe in brief.
ANSWER:
The noble enjoyed a special status in the society. He had a complete control over his property. He was the lord of all the people settled on his land. He occupied vast tracts of land which had its own dwellings, private fields, and pastures. His house was called manor. Peasants cultivated his private lands. Whenever required in battle they were also expected to act as foot soldiers.

Q3.Discuss the categories of cultivators under feudalism during the medieval age in Europe.
ANSWER:
There were two categories of cultivators in the feudal system, during the age in Europe. They were free peasants and serfs.

1. Free Peasants: They held their farms as tenants of the lord. This category of peasants did not work for their lords.
2. Serfs: Serfs were the lowest category of peasants. They were just like slaves of their masters. They had not only to work on the fields of their lords and gave them a part of their produce but also to perform such petty jobs as building or repairing their houses, roads, etc. They received no wages. They were not allowed to leave the state without the permission of their lord.

Q4.What was the position of Pope in the medieval Europe?
ANSWER:
The Pope enjoyed a respectable position in the society during the medieval period in Europe. He was considered to be the spiritual representative of Jesus Christ. He interfered into the internal affairs of the Christian kings and their subjects. Nobody could dare to challenge the authority of Pope.

Q5.What is the political importance of the feudal system?
ANSWER:
Political importance of the feudal system:

• Nobles provided protection to their people.
• They also maintained peace and harmony in their regions.
• The feeling of mutual understanding and co-operation among the people was also created.
• Through manorial system, the feudal lords provided economic provision.

Q6.Describe the merits and demerits of feudal system.
ANSWER:
Merits of the feudal system:

• Common people were provided security of life and property.
• Law and order was maintained in their territories.

Demerits of the feudal system:

• There were mutual conflicts among feudal lords to expand their own states. That is why peace and order in the society got disturbed.
• The feudal system proved to be an obstacle in the growth of political unity.

Q7.How did plague affect trade and cities?
ANSWER:

• With the expansion of trade in the 13th and 14th centuries, ships carrying goods from distant countries had started arriving in European ports. Rats came along with ships carrying away the infection of bubonic plague. After the outbreak of plague, cities became the hardest hit. In enclosed communities like monasteries, when one individual contracted the plague none survived.
• The plague took its worst toll among infants, the young and the elderly.
• As the horrible impact of plague the population of Europe, 73 millions in 1300, stood reduced to 45 millions in 1400.
• Depopulation caused a shortage of labour. Imbalance was created between agriculturalists and manufacturers.

Q8.Why did rich people donate their money to churches?
ANSWER:
The rich people donated their money to churches. The large churches were known as cathedrals. They were being built in France and belonged to monasteries. Different groups of people gave their immense contribution by their labour, materials and money for their construction. It took many years in its completion. After its completion, they became centers of pilgrimage.

Long Answer Type Question:

Q1.Discuss the following:
(i) Serf
(ii) Monk
(iii) Cathedrals
ANSWER:

• Serf: Serf occupied a distinct place in medieval Europe. They did a lot for the development of agriculture. They cultivated plots of land which belonged to the lord. A large portion of its product had to be given to the lord. They were not allowed to leave the estate without the prior permission of their lords. The lord could only decide about the marriage of their serfs.
• Monk: A group of deeply religious people chose to lead the life of isolation. They lived in religious communities called abbeys or monasteries. Monks took vows to remain in the monasteries for the rest of their lives. They spent most of their time in prayer, meditations and studies. Men or women could also lead such sort of life. Men became monks and women became nuns. There were separate monasteries for men and women. Monks and nuns did not marry.
• Cathedrals: Large churches were called cathedrals. They were built in France. Different groups of people contributed a lot to their monasteries, particularly the rich merchants. Cathedrals were built of stone. They were designed in such a way so that the priest’s voice could be heard within the hall v/here a large number of people gathered. Stained glass windows narrated the stories in the Bible through pictures. Illiterate people could also read it.

Q2.Why do you think the people of new towns were considered of fourth order? Explain.
ANSWER:
The people of new towns were considered of fourth order because of the following:

• These newly flourished towns were developed with the fair and small market centers, as a result of expansion of trade.
• The social and the political conditions of the people were totally different from the people who belonged to the former three orders.
• There were banks and lawyers in these towns. There was a distinct economic organisation in the form of guild. Each trade and craft industry was organised into a guild.
• Craftsmen found it easier to settle in the towns as goods could be produced and traded for food.
• The rich traders and merchants developed better than the nobility. They were generous to the people and engaged in trade related activities.
• Later on cathedral towns began to develop, which belonged to monastery and rich merchants.

Q3.Which causes were responsible for the rise of middle class?
ANSWER:
The causes responsible for the rise of the middle class were :

• In the crusade, a lot of feudal lords had been killed.
• The growth of commerce and trade made the trading class quite rich and prosperous. They, in turn, sought the favor of king and helped him, whenever needed.
• The wealthy merchants and rich traders got many towns and cities freed from the clutches of feudal control.
• The new cities soon grew into centers of trade, commerce and education and consequently gave rise to the new classes.
• New classes of the rich merchants patronized art, science, literature and education.

Q4.How did technological changes affect agriculture during 11th century?
ANSWER:
Technological changes affected agriculture in many ways:

• Wooden ploughs were replaced with heavy iron-tipped ploughs.
• The method of harnessing animals to the plough improved which enabled animals to exert greater power. Horses were now better shod with iron horseshoes. It prevented foot decay.
• The increased use of wind and water energy for agriculture enhanced agricultural production.
• The most innovative change was the switch from a two-field to a three field system. Now, peasants could use a field two years out of three if they planted it with one crop in autumn and a different crop in spring a year and a half later.
• Now the farmers could plant one with wheat or rye, the second in spring to raise peas, beans and lentils and the other
• part was left fallow.

As a result, there was an immediate increase in the amount of food produced from each unit of land. Food production almost doubled. There were better opportunities for cultivators. They could now produce more food for less land. The average size of peasants’ farm shrank from about 100 acres to 20 to 30 acres. As a result of holding, smaller lands could be more efficiently cultivated. It also reduced the amount of labour. The new technological changes cost a lot of money.

Q5.Discuss the achievements of the nation-states.
ANSWER:
The nation-states are known for achievements. Some of them were:

• The rise of nation-states crushed the power of the lords and this made people free from their excesses.
• They paved way for setting up peace.
• They taught the people to give support to their kings.
• They infused the spirit of nationalism among the people of different classes.
• They took remarkable steps for the consolidation of the economy of states.
• They contributed a lot in the development of language, literature and architecture.

Q6.What were the causes that led to the decline of feudalism in Europe?
ANSWER:
From the eighth to twelfth century CE, feudalism prospered in Europe. There was a steep decline of feudalism in Europe. The following causes led to its downfall:

• Rise of the powerful monarchies: Powerful monarchies paved the way for the decline of feudalism. It rose in France, Spain and England.
• Rise of nationalism: Education spread in the nation. The spread of education aroused the spirit of nationalism among the educated middle class. But the feudal lords were quite opposed to nationalism. That was why the educated people turned against feudalism. They could not tolerate its existence. They were to the side of their ruler and not with the lords. The result was that rulers became more and more powerful.
• Rise of the middle class: New inventions encouraged trade and industry. The result was the emergence of the middle class in towns and cities. The middle class desired peace for the promotion of commerce, industry and crafts. They wanted to get rid of the nobles who were always engaged in constant wars.

Short Answer Type Question:

Q1.What do you know about the Mongol? Discuss their occupations in brief.
ANSWER:
The nomadic people inhabiting in the regions of present days of Mongolia in Central Asia were known as the Mongol. They were predominantly pastoralists and hunter gatherers. They dwelt in tents and were divided into several patriarchal dynasties. They were constantly at war with other tribes like tatars, Naimans and Khitans. The main occupation of the nomadic tribe during the 12th century was pastoralism. They reared animals such as horse and sheep. In addition to these animals, they also reared goats and camels. They reared them for getting milk, meat, and wool. The geographical conditions prevailing here were not in favour of adapting agriculture. Nomadic Empires 109 Consequently, their economy was not geared to feed the regions having higher population concentration.

Q2.Write a note on the Mongol society.
Or
Describe the main characteristics of the Mongol society in 12th century.
ANSWER:

• The Mongol society was patriarchal in nature.
• The eldest male member was the head of the family who used to take care of the needs of their family members.
• The rich families were larger in size. The birth of son was highly solicited in the society.
• Polygamy was in practice in the society.
• Regarding marriage, strict rules were followed. There was ban on marriage within family circle or within a tribe.
• There were constant wars among different sections of the society.
• Some tribes with an aim to keep harmonious relations arranged marriages between their respective tribes.
•  Women were not secluded to hearth and home alone; rather than as per the needs of the hour, they used to equally assist their male counterparts in the battlefield.
• In case of death of their husbands, they too looked after children and the property of their respective families.

Q3.How did the Mongol carry out their trade?
ANSWER:
The scarcity of resources forced the nomadic tribes (the Mongols) to depend on the other neighboring countries for the essential goods for trade. Their trade was based on barter system, which was beneficial for both parties engaged in trade. They imported agricultural products and made implements from China and in line of these they used to export horses, fur and animals used for hunting. The nomadic people used to suffer less as compared to their opponents. The possible reason behind that was the nomadic people quickly disappeared from the place of their strife after carrying out loot and plunder. It meant several losses for trading partner, i.e. China. In order to safeguard their people from Mongol strife’s, the ruler of China constructed the ‘Great Wall of China’.

Q4.Write a brief description of Genghis Khan.
Or
Discuss the early career and achievements of Genghis Khan.
ANSWER:
Genghis Khan was the greatest Mongol who laid the foundation of Nomadic empire. His contribution was immense in unifying Mongols. It was due to his efforts that a vast Mongol empire was established. He was born in the year 1162. He was born near the river Onon. His father’s name was Yesugei, who was the chief of the tribe, Kiyat. His mother Oleun-eke belonged to Onggerat tribe. His original name was Temujin. He grew up as a brave man. He organized a powerful army which helped him to lay down the foundation of a vast empire. His main achievements were the conquest of Northern China, conquest of Qara Katie, etc. During the period from 1219 to 1222 CE the Mongol forces occupied Bukhara, Samarqand, Balk, Marv, Nishapur and Herat. Genghis not only built vast empire but also contributed a lot in improving the civil administration of the empire.

Q5.How did Temujin become Genghis Khan? Discuss.
ANSWER:
No doubt, Temujin was a bom commander. His initial success made him more influential. Jamuque was unable to see the growing friendly relations between Temujin and Tughril Khan. Thus, he started be-friending all the tribes hostile to Temujin. Temujin was unable to tolerate it and gave a crushing defeat to Jamuqua with the help of Tughril Khan. Encouraged by the defeat over the powerful Jamuqua, he concentrated towards Taters, Naimaans and Kereyits. Later on Tughril Khan also became hostile to Temujin and was defeated. Thus, he became the most influential person in the politics of steppe region. Keeping his achievement in mind, Quriltai awarded him with the title of Genghis Khan which means universal sovereign.

Q6.Describe in your own words the conquest of northern China by Genghis Khan.
ANSWER:
During the tenure of Genghis Khan, China was divided into three realms. These realms were North-West region, North China and South China. Each realm was governed by different ruling dynasties. His campaign against China was the result of a long drawn-out process. Northern China was invaded by Genghis Khan in 1211. It was then under the influence of Chin dynasty. The Chin ruler gave him a stiff competition. He also posed many difficulties for Genghis Khan. Tc win over him, Genghis Khan took recourse to diplomacy and instigated the people of the South Manchuria against Chin ruler. This resulted in weakening of the position of Chin ruler. Thus, he succeeded in occupying Peking in 1215. After this, Genghis Khan unleashed a reign of loot and terror in Peking. This victory of Genghis Khan encouraged his soldiers to a great extent. After this successful invasion he returned to Mongolia in 1216.

Q7.“Genghis Khan laid special emphasis on discipline in the army”. Keeping this statement in your mind, describe the rules formulated by him in the sphere of military administration.
ANSWER:
Genghis Khan made several rules in military administration with an aim to ensure discipline in the army. Some of these rules are:

• All the soldiers in the army had to obey the order of their chief commander.
• Soldiers could not take part or indulge into loot and plunder without the prior permission of their commander.
• The soldiers who were on leave immediately had to report back in case of hostilities.
• No soldier was allowed to move out of his own unit or to enter another unit.
• All the soldiers had to inspect their weapons properly before the departure for the battlefield.

Q8.Discuss the methods of the warfare of Mongol army.
ANSWER:

• Prior to any expedition, the Mongol Khan convened the meeting of the Quriltai.
• An elaborate discussion pertaining to the arms and planning for war were taken here. All the military leaders/commanders took part in it and used to receive special direction.
• The Mongol spies spread rumours in the enemy’s country, with the aim to demoralize its soldiers.
• The enemy was given the option to surrender or to face annihilation.
• After these initial preparations, when the actual war was to begin, the Mongol soldiers used to encircle the area that was to be attacked from all the sides.
• The Mongol soldiers faced the enemy’s army face to face, the tactic adopted by them was to show that they were deserting the war field. The enemy soldiers thought that the Mongol army had deserted the field. But no sooner had they reached at a particular place, the Mongol soldiers used to attack soldiers and gave them a crushing defeat.

Q9.Narrate the position of Khan in Mongol administration.
ANSWER:

• The Khan (Empire) occupied the highest rank in the administration.
• He was vested with the unlimited powers and had the authority to formulate both internal and external policies of the state.
• He was the chief commander of the army. All the armed forces of the state used to act as per his sole discretion.
• He was the sole authority to appoint all higher and civil authorities.
• He was authorized to levy any kind of new taxes.

Q10.What do you know about Ulus system? Explain.
ANSWER:
Ulus system was established by Genghis Khan. According to this system, Khan used to transfer the administration of newly conquered lands to his four sons, namely Jochi, Chaghatai, Ogedei and Toluy. His eldest son Jochi was given the region of Russian steppes. Chaghatai was given the charge of Transoxiana steppe and the region of north of Pamir Hills. It was an indication from the Khan that his third son Ogedei would succeed him as the Khan. Toluy, the fourth son was given the region of Mongolia. Ulus was not fixed. The size of Ulus used to change. Under this system, the position of the son of Khan was that of a deputy ruler. They were made the independent in-charge of the military troops, known as Tama. They (Persons holding Ulus) can appoint the person under their region and can also levy new taxes.

Q11.Write a short note on Yam.
ANSWER:
Yam was a military post, established by Genghis Khan. During the Mongol Empire, such posts were created at a distance of 25 miles. At these posts cavaliers and messengers were appointed and horses were placed at their disposal. These cavaliers used to carry official records from one place to another. Each cavalier was required to tie a bell with the neck of his horse. Whenever, a message used to reach near a post, the messenger present at post, on listening the ring of the bell so tied with the neck of horse, used to get ready along with horse to leave for the next destination. At Yam, proper arrangements were also made for the travellers. With the aim to make their stay secure and comfortable the travellers were issued official passes, known as Paiza. These passes were of three types—gold, silver and iron. The travellers had to tie these passes (Paiza) on their forehead. The travellers were provided facilities at every Yam, according to these passes. The institution proved very successful for the Mongol administration.

Q12.Describe the religious beliefs of Mongols.
ANSWER:
Religious beliefs of Mongols:

• Mongols had deep faith in religion.
• They worshiped the main deity, Tengzi, i.e. the Sun God and believed him to be omnipotent.
• In order to please their deity they used to perform animal sacrifices.
• They (Mongolian, people of Mongol) used to show special respect for holy religious man called ‘Shamans’.
• Genghis Khan believed that destiny has ordained royalty for mongers. Therefore, it is a religious obligation for the Mongol to bring more and more regions under their direct suzerainty.
• Mongols were secular in nature and followed the policy of religious tolerance. They allowed the people to respect their religion with full liberty.
• The recruitment’s under the Mongols were made only on merit basis and religion had no role to play in it.

Q13.Critically evaluate the Mongol administration.
ANSWER:
The Mongols belonged to a nomadic society. The main aim in their life was to collect booty for their survival. Mongols were much inclined towards establishing a good administration for the people being ruled by them. Their system of administration as implemented by them was at best, a makeshift effort on their part. But they did not pay heed towards the military administration. They failed to achieve anything remarkable in regard to the civil administration, which was a prerequisite for the consolidation of their empire.

Q14.What do you know about Ogodei? Write his achievements in brief.
ANSWER:
Ogodei was declared as the new Mongol Khan by Quriltai in 1229. He ruled from 1229 to 1241. After becoming the new Mongol Khan, he paid his attention towards Mughal empire. At the time of accession to power the position of Mongols in the Northern China was not much stable. In order to establish his control over Northern China, he entered into an alliance with the Sung ruler of Southern China.

• In 1234, he occupied regions of Northern China.
• In 1231, he had also inflicted a crushing defeat to the ruler of Iran Jalal-ud-din, who had escaped to India, during the time of Genghis Khan.
• Ogedei not only helped the Mongol empire to expand, rather than he also played an important role in consolidating it with an objective of strengthening the economic condition. He also regularised taxes and encouraged trade.
• He established a chain of courts in empire to give justice to all his citizens.
• To encourage education he also opened schools.
• He also did a number of civil reforms and further expanded the Yam system.

Q15.Write a short note on Jochid dynasty.
ANSWER:
Jochid dynasty was also one of the prominent dynasties of the Mongols. Jochid, the eldest son of Genghis Khan was the founder of this dynasty. Genghis Khan had transferred the region of Russian steppe to Jochid in 1224. The region of Russian steppe granted to him is also known as Southern Russia or Golden Horde. Jochid died in 1227 and was succeeded by Batu. Batu proved to be an able ruler and conquered entire Russia, Hungary, Poland and Austria during his compaigns from 1236 to 1242. He took several steps to expand Golden Horde to a large extent. He also took numerous steps to strengthen his economy and also modernised his force. After his death in 1256, his successors continued to rule up to 1359 CCE.

Long Answer Type Question:

Q1.Which favourable conditions encouraged Genghis Khan to launch an expedition against the Muhammad Shah of Khwarazm?
ANSWER:
Following favourable conditions encouraged, Genghis Khan to launch an expedition against the Shah of Khwarazm:

• Shah had established a vast empire, but nothing had been done to consolidate it.
• Shah also refused to recognise the Khalifa of Baghdad. This mistake resulted in the hostility of Muslim community against him.
• By annexation of a number of regions to his vast empire, Shah antagonised a large number of people.
• The mutual relations between Turkish and Iranian officers were not cordial. They never missed a chance to let down each other.
• He had also imposed many taxes on the farmers and general public but did care a little about their grievances. So the people wanted to get rid of such tyrannical regime.
• There was also a fear of loot and plunders. So there was restlessness among the traders as well as the common people.
• There was lack of discipline in his army.
• The continued intrigues of his mother further eroded his position. She wanted him to overthrow.

Q2.Discuss the causes of the success of Genghis Khan.
ANSWER:
Prior to his death, Genghis Khan had established a vast empire within a short span of 20 years.
Some of the main causes of his success are listed below:

• He was a born commander and distinctively fortunate to get success, wherever he went. He became a real terror of his opponents.
• He also established a large disciplined army. It was not easy to face such a huge army.
• His spies used to collect every bit of information about the opponent’s army and gave it to him.
• He knew the importance of psychological warfare and used to unleash the region of terror. In this effort, people could not face his army.
• He used to make people dread his forces, so that the people could surrender without waging a war against him.
• The Mongol soldiers were experts in horse riding and archery.
• Genghis Khan usually launched his expedition during the winter season. Because during this season rivers used to freeze and make it easier to cross them.
• The use of Naphtha Bombardment destroyed enemy forts and had dreadly results in the course of the war.

Q3.Why did Genghis Khan become unpopular? Explain.
Or
Describe the causes of the unpopularity of Genghis Khan.
ANSWER:
No doubt, Genghis Khan had established a vast empire. The newly vanquished people had no inclination towards their new ruler. Several causes were responsible for this.
The main causes were:

• The Mongols during the course of their expedition destroyed several beautiful cities and towns. Most of these cities lost their glory after his attack.
• Their invasion also badly affected the agriculture, because when the huge forces passed away they destroyed standing crops.
• During war year or the time of invasion trade and commerce was badly affected.
• A large number of people lost their lives due to their invasion. Many became handicapped and helpless.
• A number of people were slaves.
• As a result of their invasion, the timely repair to the underground rivers in the arid region was not carried out.
• All his invasions resulted in rapid desertification of newly conquered areas.
• People from all walks of life had to face hardships.

Q4.Discuss the rules and regulations of the Yasa as evolved by Genghis Khan.
ANSWER:
Rules and regulations of the Yasa:

• People should believe in one God, because He gives us life and death, riches and poverty.
• All religions are equal. They must be respected. The priests should be exempted from all kinds of taxes, transcending all religious barriers.
• Any person, who proclaimed himself to be a Khan without the recognition of Quriltai, should be awarded death penalty.
• Do not indulge into adultery. People doing so will be given death penalty.
• Do not tell a lie.
• Always respect the aged and the poor and not deceive anyone.
• It was mandatory for all able-bodied persons to serve in the army.
• On the opening of hostilities, the soldiers on leave, were asked to resume their duties immediately.
• Passion involved in spying, giving the false information/evidence/witness should be punished with death penalty.
• No one in his empire can employ a Mongol as his slave or servant.
• If a soldier indulges into loot and plunder without the prior permission of the commander, he should be awarded death penalty.
• All the Mongol princesses should preserve this Yasa, and at the time of need, they should take help from it.
• The armed forces are to be organized into units numbering 10,100, 1000 and 10000. This makes it easier for the army commander to control over military. Yasa played a remarkable role in unifying the Mongols and kept their tribal identity intact. Without any hesitation, we can say that Yasa played a remarkable role in making of global Mongol empire.

Q5.Discuss the role of civil administration in Mongol administration’
ANSWER:
Genghis Khan belonged to nomadic society. On the basis of capacity he established a vast empire. His empire included the people from various walks of society and they were civilized people. To rule such a diverse society was not an easy task. Hence, he appointed the people belonging to civilized society to look after the civil administration. The officers were concerned with civil administration and were appointed on the basis of merit. No credit was given to tribals or religious affinities while appointing them in civil administration. The civil administration played an outstanding role in strengthening and consolidating the foundation of Mongol empire. They even influenced the Mongol rulers to transform their policies pertaining to administration. He also made Genghis Khan aware about the ‘Importance of Yan system’ as followed in China.

In This Post we are  providing Chapter-4 ANIMAL KINGDOM NCERT MOST IMPORTANT QUESTIONS for Class 11 BIOLOGY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTIONS ON ANIMAL KINGDOM

Question 1.
Describe the phylum Cnidaria.

Answer:
Cnidaria is aquatic, mostly marine, sessile, or free-swimming animals. The phylum name is derived from the stinging cells (nematocysts) or cnidoblasts present on the ectoderm of tentacles and on the body of these carnivorous animals. Cnidoblasts are used for anchorage, defense, and for capture of prey. Cnidarians exhibit tissue level of organization and exhibit radial symmetry. They are diploblastic.

The digestive system is incomplete. They have a central gastro-vascular cavity with a single opening, mouth. Digestion is extracellular and intracellular. Some of the cnidarians, e.g., corals, have skeletons composed of calcium carbonate.

Cnidarians exhibit two basic body forms called a polyp (e.g., Hydra) and medusa (e.g., Auralia). The former, a sessile and cylindrical form, whereas, the latter, umbrella-shaped and free-swimming. Those cnidarians which exist in both forms exhibit alternation of generation, i.e. polyps asexually produce medusae and medusae forming the polyps sexually (e.g., Ophelia)

Examples of cnidaria: Hydra, Porpita, Vellala, Physalia (Portuguese man-of-war), Aurelia (Jellyfish), Adamisia (Sea anemone), Pennatula (Sea- pen), Gorgonia (Sea-fan), and Meandrina (Brain coral).

Some cnidarians (a) Obelia (b) Jellyfish (c) Physalia (d) Sea anemone

Polyp and medusa body from (a) sessile poy (b) swimming medusa

Structure of Hydra

Question 2.
Distinguish between the Chordates and Non-Chordates.

Answer:

Chordates	Non-Chordates
1. Notochord present.	1. Notochord absent.
2. Central nervous system is dorsal, hollow, and single.	2. Central nervous system is ventral solid and double.
3. Pharynx perforated by gill slices	3. Gill slits are absent.
4. Heart is ventral.	4. Heart is dorsal.
5. A post-anal (tail) is present.	5. Past-anal tail is absent.

Question 3.
Explain the class amphibia.

Answer:
As their name indicates (Gr. Amphi, dual, double + bios, life), most amphibians can exist in aquatic as well as terrestrial habitats. Most of them have two pairs of limbs. The body is divisible into the head and trunk; the tail may be present in some. The amphibian skin is moist (without scales). The eyes have eyelids. A tympanum represents the ear.

The alimentary canal, urinary and reproductive tracts open into a common chamber called the cloaca, which opens to the exterior through an aperture called the cloacal aperture. Respiration may be by gills, lungs, or through the skin. The heart is three-chambered (2 auricles and 1 ventricle). These are cold-blooded animals.

Sexes are separate Fertilization is external. They are oviparous and development is direct or indirect.

Examples of Amphibia: Bufo (Toad), Rana (Frog), Hyla (Tree frog),

Salamandra (Salamander), Ichthyophis (Limbless amphibia).

Frog

Question 4.
Describe the class Reptilia.

Answer:
The class name refers to their creeping or crawling mode of locomotion. They are mostly terrestrial animals with a body covered by dry and cornified skin, epidermal scales, or scutes. They do not have external ear openings. Limbs, when present, are two pairs. The heart is usually three-chambered, but four-chambered in crocodiles, Reptiles are cold-blooded animals. The excretory organ is the kidney. Snakes and lizards shed their scales as skin cast.

Sexes are separate. Fertilization is internal. They are oviparous and development is direct.

Examples of Reptilia T Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Naja (Cobra), Crocodilus (Croco¬dile), Aligator (Alligator).

(a) Tortoise, (b) Monitor (Indian goh) (c) Naja (d) Crocodile (e) Chameleon

Question 5.
Explain the important characteristics of Mammalia.

Answer:
Mammalia is generally terrestrial, found in a variety of habitats- polar ice caps, deserts, mountains, forests, grasslands, and dark cover. Some of them have even adapted to fly or live in water. The most unique mammalian characteristic is the presence of milk-producing glands (mammary glands) by which the young ones are nourished.

Mammalia has two pairs of limbs, which are variously adapted for walking, running, climbing, burrowing, swimming, and flying. The skin of mammals is unique in possessing hairs. External ears or pinnae are present. Different types of teeth are present in the jaw. The heart is four-chambered. The lungs are well developed. Mammals show the greatest intelligence among all the animals.

Sexes are separate and fertilization is internal. They are viviparous with few exceptions and development is direct.

Some mammals:

Ornithorhynchus

Balaenoptera

Pteropus

Macropus

Question 6.
Describe the main characteristic of class-Aves.

Answer:
The characteristic features of birds are the presence of feathers and most of them can fly with few exceptions, generally called flightless birds (e.g. Ostrich). They possess beak. The forelimbs are modified into wings. The hind limbs generally have scales and are modified for walking, swimming, or clasping the tree branches. Skin is dry without glands except for the oil gland at the base of the tail. The endoskeleton is fully ossified (bony) and the long bones are hollow with air cavities.

The digestive tract of birds has additional chambers, the crop, and the gizzard. The heart is completely four-chambered. They are warm-blooded (homeotherms) animals, i.e., they are able to maintain constant body temperature. Respiration is by lungs that contain air sacs. Birds have a good sense of sight. The excretory organ is a kidney.

Sexes are separate. Fertilization is internal. They are oviparous and development is direct. Examples of Aves are Corvus (crow), Columba (pigeon), Prittacula (parrot), Struthio (Ostrich) Paver (Peacock), Aptenodytes (Penguin)

Some birds : (a) Neophron (b) Struthio (c) Psittacula (d) Pavo

Question 7.
Write some basic characterize- features of the following Phyla:
Ctenophora, Annelida, Mo.llusca, Echino Desmata and Hemichordata.

Answer:
Represents some basic characteristic features of different phyla.

Question 8.
Draw the diagram of the classification of phylum Chordata.
Answer:

Classification of phylum Chordata

Question 9.
Describe the phylum Arthropods.

Answer:
The phylum Arthropoda is the largest phylum of the animal kingdom consisting of more than 900,000 species, which include many economically important insects.

1. They have an organ-system level of body organization. They are bilaterally symmetrical, triploblastic, segmented, and acoelomate animals.
2. The body of arthropods is covered by a chitinous cuticle which forms the exoskeleton. The body segments are fused to form the head, thorax, and abdomen.
3. They have jointed appendages. The appendages are variously modified to form antennae, mouthparts, pincers (chelicerae), or walking legs.
4. The digestive system is complete.
5. Respiratory organs are gills, book gills, book lungs, or tracheal system.
6. The circulatory system is open type.
7. The nervous system is almost similar to that of the annelids. Sensory organs include antennae for perceiving odor, receptors for taste, eyes (compound and simple), statocysts or balance, organs, and sound receptors.
8. Excretion takes place through green glands or malpighian tubules.
9. They are mostly dioecious. Reproduction is sexual. Fertilization is usually internal. They are mostly oviparous.

Development may be direct or indirect, passing through many larval stages. The process of transformation of a larva into an adult is called metamorphosis.

Some common arthropods (a) Centipede (b) Millipede (c) Beetle (d) Prawn (e) Spider and (f) Scorpian

Examples of Arthropoda: Araneus (Garden spides), Limulus (King crab),

Buthus (Scorpion), Scolopendra (Centipede), Cancer (Common crab), Balanus (Barnacle), Lepisma (Silverfish), Periplaneta (Cockroach), Apis (Bee) Anopheles (Mosquito), Musca (Housefly), Charaxes (Butterfly), Attelabus (Beetle), Locusta (Locust) and An ax (Dragonfly).

Question 10.
Describe the phylum Porifera.

Answer:
Members of this phylum are commonly known as sponges. They are generally marine, diploblastic bilaterally symmetrical with a significant water transport mechanism. They are considered as very primitive multi-cellular animals and have a cellular level of organization.

Water can enter through minute pores (Ostia) in the body wall directly or through the canal into a central cavity, spongocoel, from where it goes out through the osculum.

This pathway of water transport is called the canal system and is helpful in food gathering, respiratory exchange, and removal of water. Choanocytes or collar cells line the spongocoel and the canals. Digestion is intracellular. The body is supported by a skeleton made up of spicules or spongin fibers.

Sexes are not separate (monoecious/hermaphrodite/bisexual), i.e., eggs and sperms are produced by the same individual. Sponges reproduce asexually by fragmentation and sexually by the formation of gametes. Fertilization is internal and development is indirect having a larval stage that is morphologically distinct from the adult.

Examples of Porifera are Sycon (Scypha), Spongilla, Chalina, (Dead man’s finger), and Euspongia (Bath sponge)

Examples for Porifera: (a) Sycon (b) Euspongia (c) Spongilla

In This Post we are  providing Chapter-3 PLANT KINGDOM NCERT MOST IMPORTANT QUESTIONS for Class 11 BIOLOGY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter

NCERT MOST IMPORTANT QUESTIONS ON PLANT KINGDOM

Question 1.
How do red algae differ from brown algae?

Answer:
Differences between red algae and brown algae:

Red algae	Brown algae
1. Unicellular and microscopic only a few are filamentous and Heterotrichous.	1. Filaments and heterotrichous.
2. Phycoerythrin, phycocyanin and phycobilins pigments are present.	2. Fucoxanthin pigment is present.
3. Reserve food material is Floridian starch.	3. Reserve food material is Laminarian starch.
4. Chlorophyll ‘a’ present.	4. Chlorophyll ‘a’ + ‘c’ present.
5. e.g. Gelidium Polysiphonia.	5. e.g. Laminaria, Fucus and Surgaassum.

Red algae

Porphyra or Polysiphonia

Question 2.
Distinguish the reproductive organs of gymnosperms and angiosperms.

Answer:

Gymnosperms	Angiosperm
1. The sporophylls are aggregated to form cones.	1. The sporophylls are aggregated to produce flowers.
2. Microporosphyll consists of micro-sporangia bearing microspores.	2. Microsporophyll is differentiated into anther and filament.
3. Stigma and style are absent.	3. Stigma and style are present.
4. Ovule lies on the lower side and exposed to the megasporophyll.	4. Ovules are attached to the funic-ulus and are present inside the ovary.
5. One too many cotyledons are present.	5. One or two cotyledons are present.
6. Fruit formation doesn’t take place.	6. Fruit formation takes place.
7. Double fertilization is absent.	7. Double fertilization is present.
8. Archaegonia are present.	8. Archaegonia are present.

Question 3.
Mention the changes that take place when the fruit ripens.
Answer:

1. Starch is converted into sugar.
2. The production of various organic substances gives it a texture, taste and flavour.
3. The breakdown of chlorophyll leads to changes in the colour of the skin of the fruit.

Question 4.
Describe the important characteristics of gymnosperms.

Answer:
Characteristic features of gymnosperms:

1. Gymnosperms are evergreen woody, perennial plants.
2. Plants are heterosporous.
3. Reduction of gametophytic generation.
4. The enclosure of the female gametophyte by the megasporangium.
5. Ovules are exposed to receive pollen grains.
6. Gymnosperms possess exposed or naked seeds.
7. Polyembryony is a common occurrence.
8. Xylem lacks vessels and phloem lacks companion cells. Example Cycas, Pinus and Cedms.

Question 5.
Explain briefly the alternation of generation in bryophytes.

Answer:
Alternation of generations: Moss plants are a gametophyte. Spore is the beginning of the gametophytic generation. It develops into protonema which rises to male and female gametes produced in them. Club-shaped antheridium bears biflagellate sperms or antherozoids. Flask-shaped archegonium encloses the female egg. a zygote is formed after the fertilization (syngamy) of male and female gametes with the help of water

Repeated divisions of the zygote give rise to the embryo (2n) which soon develop into a sporophyte. The sporophyte of moss gets differentiated into three parts -foot, seta and capsule. Inside the capsule, single-celled spores are produced. After the dehiscences, they begin to germinate and give rise to the protonema to start the cycle again. Gametophytic generation alternates the sporophytic generation.

Question 6.
Draw the diplontic and haplo-diplontic cycles.
Answer:

Diplontic cycles

Haplo-diplontic cycles

Question 7.
What are angiosperms? Give their characteristic features.

Answer:
Angiosperms are a group of flowering plants where seeds are embedded in the fruits.

They show the following characters:

1. The ovules/seeds are enclosed within the ovary, or we may say that after fertilization seeds are located in the fruit.
2. Male and female gametes i.e. pollen grains and egg nucleus are borne by the flowers.
3. During pollination pollen grains fall on the stigma, they develop on the stigma of the ovary and male gametes enter the egg nucleus through Onicropyh.
4. Male gametophyte is a three-celled structure when dehisced.
5. Embryosac or female gametophyte is eight celled when young and becomes seven celled at the time of fertilization.
6. There is double fertilization wherein one male gamete fuses with the egg nucleus to form a diploid zygote and another fuse with the secondary nucleus to form a triploid endosperm.
7. Xylem consists of tracheids, vessels fibres and parenchyma while phloem consists of sieve tubes, companion cells and phloem parenchyma and fibres. Xylem conducts water to the tip of tall trees and phloem is responsible for the translocation of food.

Question 8.
Write brief notes on:

(i) Green algae
Answer:
Green Algae: The Class (Chlorophyta: ‘GK’ choros = green: phyton = plant) has over 7,000 species. They are in several shapes and sizes. Some are unicellular and microscopic. Some are motile colonies like Volvox. Some, are multinucleated but unicellular i.e. coenocytic like cholera.

Volvox

Chlamydomonas

Chara

(ii) Brown algae
Answer:
Brown Algae: The Class (Phaeophyta: GK: pharos = brown: phyton = plant) has about 2,000 species, mostly marine. Some of, the world’s largest sea plants measuring 40-60 metres long. Brown algae occur chiefly in cooler seas. Some are filamentous. Brown algae like Laminaria are attached firmly to the rocks below by holdfasts.

Laminaria

Fucus

Dictyota

(iii) Club moss
Answer:
Club mass: It belongs to Lycopsida. In most parts of the world, Lycopodium is found. Sporangia’ are produced on mature leaves.

(iv) Horsetail
Answer:
Horsetail: Also called Sphenopsida. This group exists only Equisetuin. Because they look like the tail of a horse, so they are called horsetail. These plants are up to 1 metre in length. But some extinct species are of several metres. The root, stem and leaves are true.

(v) Sporophyll
Answer:
SporphyMs: They are special spore-bearing leaves and. produce sporangia in sori on their underside, where haploid spores are formed by meiosis. Spores germinate to form an independent, small gametophyte, the prothallus. This bears archegonia and antheridia. Male gamete from antheridia and swim in a film of water to egg cells in archegonia and fertilize them.

Question 9.
Discuss the development of seed habit.

Answer:
The seed plants have two kinds of sporangia. These sporangia are born on the sporophylls.

One type of sporangia are ovule or megasparangium. The other type of sporangia is the pollen sac or archegonium. The egg develops a pollen sac or microsporangium. The egg develops in the ovule from the megaspores. Many pollen grains are produced in the pollen sac.

The pollen grains are dispersed by the air! They reach the ovule. The male gamete and the female egg cell fuse together. The zygote is formed as a result of fertilization. Later on, the zygote forms the embryo. The seed is developed from the ovule. The development of seed habit in gymnosperm and angiosperm do not require liquid water during fertilization

Question 10.
What are the different lifestyles shown by Angiosperms?
Answer:

1. Hydrophytic plants are the plants that live in water or swampy places. Hydrophytes are categorised into, two groups:
   (a) Submerged plants like Hydrilla, Vallisneria, Utriculria and
   (b) Floating plant-like Nymphea, Wolffia and Pistia.
2. Xerophytic plants are those plants that live in the scarcity of water e.g. cactus.
3. Halophytes are a type of xerophytic plants that are present in saline conditions.
4. Insectivorous plants-A few angiosperms, though green and autotrophic trap insects to overcome the shortage of nitrogen. For example, pitcher plant, sundew, bladderwort.

In This Post we are  providing Chapter-2 BIOLOGICAL CLASSIFICATION NCERT MOST IMPORTANT QUESTIONS for Class 11 BIOLOGY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTIONS ON BIOLOGICAL CLASSIFICATION

Question 1.
What are imperfect fungi?

Answer:
Asexually reproducing fungi belonging to Deuteromycites are imperfect fungi

Question 2.
How many basidiospores are formed after Karyogamy and meiosis?

Answer:4

Question 3.
What is plasmogamy?

Answer:
Fusion of protoplasms between two motile or non-motile gametes.

Question 4.
What are the slime molds?

Answer:
1. The slime molds are both plant and animal-like.

2. They are plant-like in the production of spores during reproduction and animal-like in the mode of nutrition and rheumatic organization.

3. Their rheumatic structure consists of an acellular, multinucleate mobile mass of protoplasm which lacks a good wall called plasmodium.

4. The reproductive stage consists of sporangia and spores formed after meiosis. The spores on germination produce either flagellated swarm cells or myxamoebae.

5. These divide mitotically, then behave as gametes and fuse in pairs to form a diploid zygote. The zygote nucleus divides mitotically but the nuclear division is not followed by cell wall formation so that all nuclei lie free in the cytoplasm.

6. The enlargement of the zygote into plasmodium takes place which moves freely on the substratum and feeds on bacteria, fungal and algal spores, and also absorbs nutrients directly from the substratum. The plas¬modium then settles on dry places and develops into sporangia. Therefore asexual stage is plant-like and the sexual stage is animal-like.

Question 5.
Write a short note on kingdom Plantae.

Kingdom Plantae

Answer:
1. Kingdom Plantae includes all autotrophic plants which are photosynthetic forms called green plants starting from simple algae, bryophytes, pteridophytes to gymnosperm and angiosperms.

2. The plant cell has a cell wall mainly made of cellulose and, eukaryotic structure with prominent chloroplasts. Some plants are heterophilic like insectivorous plants which feed on insects and flies e.g. Bladderwort and Venus flytrap.

(3) The life cycle has two phases-sporophytic and gametophytic which are diploid (2n) and haploid (n) respectively. That means zygote (2n) undergoes meiosis to form haploid (n) spores these spores germinate into a gametophyte, then these gametes (male and female) fuse to form a zygote (2n) again which gives rise to the sporophyte. This phenomenon is called the alternation of generation.

Question 6.
Write a short note on Mycoplasma.

Answer:

1. Discovered by E.Nocard and E.R. Roux (1998) mycoplasma is the smallest known aerobic prokaryotes without a cell wall.
2. They were isolated from cattle suffering from bovine pleuropneumonia and hence they were designated as PPLO (pleuropneumonia-like organisms)
3. They are found in different forms as a spheroid, thin, stellate called pleomorphic.
4. They occur in soil, sewage, human, and plants.

Question 7.
Write a short note on Kingdom Animalia.

Answer:

1. Kingdom Animalia includes all animals except the protozoan. The members are multicellular eukaryotes. The cell wall is absent cells, organized into tissue. They directly or indirectly depend on plants for food.
2. They digest their food in an internal cavity and store food reserves as glycogen or fat. They are heterotrophic and the mode of nutrition is holozoic nutrition. They act as decomposers and help in the recycling of minerals.
3. Kingdom Plantae includes the multicellular, photosynthetic eukaryotic forms.
4. They have well-established mechanisms for absorption and Kingdom Animalia includes all animals except the protozoans. They are multicellular eukaryotes and are holozoic. The cells lack walls.

Question 8.
Write a short note on Lichens.

Answer:
Lichens are a symbiotic association between algae and fungi. The algae component is known as phycobiont and the fungal component as mycobiont which are autotrophic and heterotrophic respectively. Algae prepare food for fungi and fungi provides shelter and absorbs mineral nutrient and water for its partner.

On the basis of the structure of thallus, lichens can be classified into three types

1. Crustose: forms a crust on the substrate which is not easily separated from the substrate e.g. Graphis
2. Foliose: forms the leafy lobed structure attached to the substrate with the help of rhizines easily separated from substrate eg. Parmelia.
3. Fruticose: forms shrubby, cylindrical, and branched thallus. They grow erect or hang from the substrate e.g. Usnea. Lichens are the pioneer colonizers of bare rocks. They also colonize tree trunks in temperate climatic regions.

Question 9.
Describe the kingdom Monera.

Answer:
This kingdom comprises single-celled prokaryotic organisms like bacteria, filamentous actinomycetes, and photosynthetic blue-green algae of Cyanobacteria. The salient features are already given in Table 2.1 we will further discuss the following organisms briefly.

Bacteria: Bacteria are single-celled microscope true prokaryotic organisms which are almost omnipresent. They colonize soil, water, and air. These can survive

in extreme environmental conditions like high temperature, high salt concentration, in absence of oxygen (anaerobic) or in presence of oxygen (aerobic) in high acidic or alkaline pH, etc. (sometimes these are called Archaebacteria).

Some bacteria can be chemotrophs that derive energy from inorganic compounds in absence of oxygen e.g. methanogenic bacteria produce methane gas (CH₄) from CO₂ and H₂, some live by oxidizing hydrogen supplied eg. Thiothsix.

Some are parasites on plants and animals e.g. Xanthomonas citri and Vibrio Cholera; another form symbiotic association with plant roots e.g. Rhizobium.

The bacteria can be of various sizes and shape i.e. spherical or round, coccus (pi. cocci), rod-shaped and bacillus (pi. Bacilli), spiral-shaped spirillum (pi. Priscilla). Long and helical shaped called spirochetes. Many bacteria have one or more slender, long flagellum (pi. flagella) which helps them to move in the liquid substrate. Some bacteria form endospores under poor nutrient conditions.

Question 10.
Write the distinct characters of protozoa.

Answer:
1. Protozoa are single-celled heterotrophs or ‘first animal’. They can be free-living and parasitic members, mobile with flagellar movement, by pseudopodia, or by ciliary movements e.g. Euglena and Amoeba.

2. Cell wall is absent in some like Amoeba so they can change their shape. The Euglena is autotrophic because of the presence of chlorophyll it performs photosynthesis but in the absence of light, it becomes heterotropic and ingests other protists or food particles.

3. They reproduce asexually by binary fission but some reproduce sexually by fusion of gametes followed by meiosis. Another important member of protists is the malarial parasite, Plasmodium, causing the notorious disease malaria in man, carried by mosquitoes, it multiplies rapidly in the liver of humans and brings about the cyclic fever releasing toxins into the bloodstream of its host.

Photograph of Amoeba and Euglenas

In This Post we are  providing Chapter-1 THE LIVING WORLD NCERT MOST IMPORTANT QUESTIONS for Class 11 BIOLOGY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTIONS ON THE LIVING WORLD

1. Why are living organisms classified?

Sol. Living organisms are classified because of the following reasons:
(i) Easy identification.
(ii)Study of organisms of other places.
(iii)Study of fossils
(iv)Grouping helps in study of all types of organisms while it is impossible to study individually all of them.
(v) Itbringsoutsimilaritiesanddissimilarities. They help in knowing relationships among different groups.
(vi)Evolution of various taxa can be known.

2. Why are the classification systems changing every now and then?

Sol. From very early days till now biologists use several characters for classification system. These are morphology, anatomy, cytology, physiology, ontogeny, phylogeny, reproduction, biochemistry, etc. But day by day biologists are learning something new about organisms from their fossil records and using” advanced study techniques such as molecular phylogeny, etc. So their point of view about classification keeps changing. Thus the system of classification is modified every now and then.

3. What different criteria would you choose to classify people that you meet often?

Sol. The various criteria that may be chosen to classify people whom we meet often include behaviour, geographical location, morphology, family members, relatives, friends etc.

4. What do we learn from identification of individuals and populations?

Sol. The knowledge of characteristic of an individual or its whole population helps in identification of similarities and dissimilarities among the individuals of same kind or between different types of organisms. It helps us to classify the organisms in various categories depending upon these similarities and dissimilarities.

5. Given below is the scientific name of mango. Identify the correctly written name.
Mangifera Indica Mangifera indica

Sol. The correctly written scientific name of mango is Mangifera indica.

6. Define a taxon. Give some example of taxa at different hierarchical levels.

Sol. A taxonomic unit in the biological system of classification of organism is called taxon (plural taxa). For example a phylum, order, family, genus or species represents taxon. It represents a rank. For example, all the insects form a taxon. Taxon of class category for birds is Aves and taxon of Phylum category for birds is Chordata. The degree of relationship and degree of similarity varies with the rank of the taxon. Individuals of a higher rank, say Order or Family, are less closely related than those of a lower rank, such as Genus or Species.

7. Can you identify the correct sequence of taxonomical categories?
(a) Species —> Order —> Phylum —> Kingdom
(b) Genus—) Species—> OrderKingdom
(c) Species —> Genus —>Order —> Phylum

Sol. The correct sequence of taxonomical categories is
(c) i.e., Species —>Genus —> Order —> Phylum.

8. Try to collect all the currently accepted meanings for the word ‘species’. Discuss with your teacher the meaning of species in case of higher plants and animals on one hand, and bacteria on the other hand.

Sol. Species occupies a key position in classification. It is the lowest taxonomic category. It is a natural population of individuals or group of populations which resemble one another in all essential morphological and reproductive characters so that they are able to interbreed freely and produce fertile offsprings. Each species is also called genetically distinct and reproductively isolated natural population. Mayr (1964) has defined species as “a group of actually or potentially interbreeding populations that are reproductively isolated from other such groups”.
In higher plants and animals the term ‘species’ refers to a group of individuals that are able to interbreed freely and produce fertile offsprings. But, in case of bacteria interbreeding cannot serve as the best criteria for delimiting species because bacteria usually reproduce asexually. Conjugation, transformation and transduction, which are termed as sexual reproduction methods in bacteria, also do not correspond to true interbreeding. Thus, for bacteria many other characters such as molecular homology, biochemical, physiological, ecological and morphological characters are taken into consideration while classifying them.

9. Define and understand the following terms:
(i) Phylum (ii) Class (iii) Family
(iv) Order (v) Genus

Sol. (i) Phylum – Phylum is a category higher than that of Class. The term Phylum is used for animals. A Phylum is formed of one or more classes, e.g., the Phylum Chordata of animals contains not only the class Mammalia but also Aves (birds), Reptilia (reptiles), Amphibia (amphibians), etc. In plants the term Division is used in place of Phylum.
(ii) Class – A Class is made of one or more related Orders. For example, the Class Dicotyledoneae of flowering plants contains all dicots which are grouped into several orders (e.g., Rosales, Sapindales, Ranales, etc.).
(iii) Family, – It is a taxonomic category which contains one or more related genera. All the genera of a family have some common features or correlated characters. They are separable from genera of a related family by important and characteristic differences in both vegetative and reproductive features. E.g., the genera of cats (Fells) and leopard (Panthera) are included in the Family Felidae. The members of Family Felidae are quite distinct from those of Family Canidae (dogs, foxes, wolves).
Similarly, the family Solanaceae contains a number of genera like Solanum, Datura, Petunia and Nicotiana. They are distinguishable from the genera of the related family Convolvulaceae (Convolvulus, Ipomoea).
(iv) Order – The category includes one or more related families. E.g., the plant Family Solanaceae is placed in the Order Polemoniales alongwith four other related families (Convolvulaceae, Boraginaceae, Hydrophyllaceae and Polemoniaceae). Similarly, the animal families Felidae and Canidae are included under the Order Carnivora alongwith Hyaenidae (hyaenas) and Ursidae (bears).
(v) Genus – It is a group or assemblage of related species which resemble one another in certain correlated characters. Correlated characters are those similar or common features which are used in delimitation of a taxon above the rank of species. All the species of genus are presumed to have evolved from a common ancestor. A genus may have a single living species e.g., Genus Homo. Its species is Homo sapiens – the living or modem man. The Genus Felis has many species, e.g., F. domestica – common cat, F. chaus (jungle cat) etc.

10.How is a key helpful in the identification and classification of an organism?

Sol.‘Key is an artificial analytic device having a list of statements with dichotomic table of alternate characteristics. Taxonomic
keys are aids for rapid identification of unknown plants and animals based on
the similarities and dissimilarities. Keys are primarily based on stable and reliable characters. The keys are helpful in a faster preliminary identification which can be backed up by confirmation through comparison with detailed description of the taxon provisionally identified with. Separate taxonomic keys are used for each taxonomic category like Family, Genus and Species.

In This Post we are  providing Chapter-7 ENVIRONMENTAL CHEMISTRY NCERT MOST IMPORTANT QUESTIONS for Class 11 CHEMISTRY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTIONS ON ENVIRONMENTAL CHEMISTRY

1.What is troposphere?

Ans:The lowest region atmosphere in which the human beings along with other organisms live is called troposphere. It extends upto the height of km from sea level.

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2.Name some gaseous air pollutants.

Ans:Gaseous air pollutants are oxides of sulphur, nitrogen and carbon, hydrogen sulphide, hydrocarbons, ozone and other oxidants.

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3.What are the diseases caused by sulphur dioxide?

Ans:Sulphur dioxide causes respiratory diseases eg. asthma, bronchitis, emphysema in human beings, sulphur dioxide causes irritation to the eyes, resulting in tears and redness.

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4.List gases which are responsible for green house effect?

Ans:Carbon dioxide, methane, water vapors, nitrous oxide, CFC’s and ozone are responsible for green house effect.

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5.What is the effect of CFC’s on ozone layer?

Ans: 02Chlorofluorocarbon (CFC’s) damage the ozone layer and creates holes in ozone layer.

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6.What is greenhouse effect?

Ans:Atmosphere traps the Sun’s heat near the Earth’s surface and keeps it warm. This is Greenhouse effect.

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7.Which disease is caused due to ozone layer depletion?

Ans:Ultraviolet rays reaching the earth passing through the ozone hole cause skin cancer.

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8.What is smog?

Ans: When smoke with fog, it is called smog.

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9.The London smog is caused in which season and time of the day?

Ans: The London smog is caused during summer season and in the afternoon part of the day when it is very hot.

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10.Name two gases which form acid rain.

Ans: 04SO₂ and NO₂.

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11.Which acid is present is the acid rain?

Ans: 05The acids present in the acid rain are

H₂SO₄, HNO₃ and HCl.

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12.What is PAN?

Ans: 06PAN is Peroxy acetyl nitrate.

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13.When does rain water become acid rain?

Ans: 08When pH of rain water becomes as low as 2 to 3.5. It forms acid rain.

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14.What is BOD?

Ans: 01BOD stands for Biochemical Oxygen Demand.

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15.Define green chemistry.

Ans: 03The branch of chemistry that emphasizes on the processes and products that reduce or eliminate the use and generation of toxic / hazardous substances is called green chemistry.

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In This Post we are  providing Chapter-6 HYDROCARBONS NCERT MOST IMPORTANT QUESTIONS for Class 11 CHEMISTRY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTIONS ON HYDROCARBONS

Question 1.
The following organic compounds are known by their common names

(i) Neopentane
Answer:
Neopentane is

& its h.U.P.A.C. name is 2, 2—dimethyl propane.

(ii) Acetone
Answer:
Acetone is

and its I.U.P.A.C. name is Propanone.

(iii) Vinyl chloride
Answer:
Vinyl chloride is CPU = CH — Cl and its I.U.P.A.C. name are chloroethene.

(iv) Tert butyl alcohol. Write their structural formulae and I.U.P.A.C. names.
Answer:
Tert; butyl alcohol

and its I.U.P.A.C. name is 2-methyl propan-2-ol.

Question 2.
What are the various products expected when propane reacts with fuming nitric acid?

Answer:

Question 3.
How will you convert methane into
(i) Methanol

Answer:
Conversion of methane into methanol:

(ii) Methanal.

Answer:

Question 4.
What is aromatization? How will you convert ^hexane into benzene?

Answer:
Aromatization. It is the process that involves cyclization, isomerization, and dehydrogenation with the application of heat and catalyst to convert alkanes containing six or more carbon atoms into aromatic hydrocarbons.

Question 5.
Give the different conformations of ethane with their
(i) Sawhorse representation and
(ii) Newmann Projection formulae.

Answer:
Sawhorse representation Newmann projection models

Question 6.
What are the relative stabilities of different conformations of ethane? Is it possible to isolate these at room temperature?

Answer:
The staggering form of ethane is more stable than the eclipsed form because the force of repulsion between hydrogen atoms on adjacent C atoms is minimum. The energy difference between the staggered form and eclipsed form of ethane is just 12.55 kJ mol^-1. Therefore, it is not possible to separate these two forms of ethane at room temperature.

Question 7.
What is Saytzeff Rule? What are the expected products when 2-Bromobutane is dehydrohalogenation with ale. KOH?

Answer:
Saytzeff Rule. Whatever two alkenes are theoretically possible during a dehydrohalogenation reaction, it is always the more highly substituted alkene that predominates.

Question 8.
What is the order of reactivity of H₂C = CH₂, (CH₃)₂, H₂C = CH₂, CH₃ – CH = CH₂, CH₃ – CH = CH – CH₃, (CH₃)₂ C = C (CH₃)₂, (CH₃)₂ C = CH CH₃ towards electrophilic addition reactions?

Answer:
The order of reactivity of the above alkenes towards electrophilic addition reactions decreases in the order.
(CH₃)₂ C = C (CH₃)₂ > (CH₃3)₂ C = CH CH₃ > (CH₃)₂ C = CH₂ > CH₃ CH – CH – CH₃ > CH₃ – CH = CH, > CH₂ = CH₂.

Question 9.
Define Markownikov rule. Explain it with an example.

Answer:
Markownikov rule states. The negative part of the addendum adding to an unsymmetric alkene goes to that C atom of the double bond which is attached to a lesser number of C atoms.

Question 10.
What is the Peroxide effect/Kharasch Effect? Illustrate with an example.

Answer:
In the presence of peroxides such as benzoyl peroxide, the addition of HBr (but not of HCl or HI) to an unsymmetrical alkene takes place contrary to the Markownikov rule. This is known as the peroxide/Kharsch effect.

In This Post we are  providing Chapter-5 ORGANIC CHEMISTRY: SOME BASIC PRINCIPLE AND TECHNIQUE NCERT MOST IMPORTANT QUESTIONS for Class 11 CHEMISTRY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTIONS ON ORGANIC CHEMISTRY: SOME BASIC PRINCIPLE AND TECHNIQUE

Question 1.
Without using column chromatography, how will you separate a mixture of camphor and benzoic acid?

Answer:
Sublimation cannot be used as both camphor and benzoic acid sublime on heating. Therefore, a chemical method using NaHCO₃ solution is used when benzoic acid dissolves leaving camphor behind. The filtrate is then cooled with dilute HCl to get benzoic acid.

Question 2.
Compare inductive & mesomeric effects.

Answer:

Inductive effect	Mesomeric effect
1. It operates in saturated gp. of compounds.	1. It occurs in unsaturated & especially in conjugated compounds.
2. It involves electrons in σ – bonds.	2. It involves electrons in π – bonds.
3. Electron pair is slightly displaced & there only partial charges are developed.	3. The electron pair is transferred completely with the result full positive & negative charges are created.
4. It is transmitted over only a quite short distance.	4. It is transmitted from one end to the other of quite large molecules provided conjugation (i.e. delocalised orbitals) is present through which it can proceed.

Question 3.
What is the difference between distillation, distillation under reduced pressure & steam distillation?

Answer:

Distillation	Distillation under reduced pressure	Steam distillation
This is used to separate volatile liquid from non-volatile liquid or solid separately.	This is used to purify liquids that decompose at or below their boiling points.	This is used for purifying substances that are steam volatile & immiscible with water.

Question 4.
How will you purify sugar which has impurities of sodium chloride?

Answer:
Sugar may be purified by the crystallization method. This can be purified by shaking the impure solid with hot ethanol at 345K. The sugar will dissolve whereas common salt remains insoluble. The hot solution is filtered, concentrated & allowed to cool when crystals of sugar will separate out. In this case, hot water has been used as a solvent. The purification of sugar would not have been possible since both sugar’& common salt are soluble in water.

Question 5.
Differentiate between Ionic & free radical reactions.

Answer:

Ionic reactions	Free radical reactions
1. These occur only rarely in the gas phase but mainly in a solution of polar solvents; the reaction is influenced by the polarity of the solvent.	1. These occur in gas phases or in non-polar solvents.

Question 6.
For each of the following compounds, write a more condensed formula & also their bond-line formula.

(b) HOCH2CH2CH2CHCH3CHCH3CH3

Answer:

Question 7.
Expand each of the following bond line formulae to show all the atoms including carbon & hydrogen.

Answer:

Answer:

Answer:

Question 8.
Explain why is (CH₃) C+ more stable than CH₃ C⁺ H₂ & C⁺ H₃ is the least stable cation?

Answer:
Hyperconjugation interaction in (CH₃)₃ C⁺ is greater than in C+⁺ H₃ C⁺ H₂ has 9 C -H bonds. In C H₃, the C -H bonds are in the nodal plane of the vacant 2p-orbital & hence cannot overlap with it.
Thus C⁺ H₃ is least stable.

Question 7.
The choice of the solvent is of great importance in crystallizing organic substances. What are the characteristics of a suitable solvent?

Answer:
A suitable solvent must have the following characteristics;

1. The impurities & pure compound must have a large difference in their solubilities.
2. The pure compound must have low solubility at room temperature but high solubility at its boiling point.
3. The impurity should either be insoluble at room temperature or must have high solubility so that crystallization may give a high yield.
4. The solvent should have an average boiling point.
5. The solvent should neither react with the compound nor with impurities.
6. The solvent should not be highly inflammable.

Question 8.
Explain the principle of steam distillation.

Answer:
Steam distillation: The process of steam distillation is employed in the purification of substance from non-volatile impurities provided the substance itself is volatile in steam and insoluble in water.

This method is based on the facts that

1. A liquid boils at a temperature when its vapour pressure becomes equal to the atmospheric pressure.
2. The vapour pressure of a mixture of two immiscible liquids is equal to the sum of the vapour pressures of the individual liquids.

In the actual process, steam is continuously passed through the impure organic liquid. Steam heats the liquid and it gets practically condensed to water. After some time mixture of the liquid and water begins to boil, because the vapour pressure of the mixture becomes equal to the atmospheric pressure.

Obviously, this happens at a temperature that is lower than the boiling point of the substance or that of water. Thus an organic compound boils below its boiling points and chances of decomposition avoided. For example, a mixture of aniline (b.p 453 K) with decomposition and water (b.p. 373 K) under normal atmospheric pressure boils at 371K. At this temperature the

Steam Distillation

water boils at 371 K. At this temperature, the vapour pressure of water is 717 mm and that of aniline is 43 mm and therefore the total pressure is equal, to 760 mm. Thus in steam distillation, the liquid gets distilled at a temperature lower than its boiling point and chances of decomposition avoided. The proportion of water and liquid in the mixture that distils over is given by the relation.

w1w2=P1×18P2×M
where w₁ and w₂ stand for the masses of water and liquid that distils over. P₁ and P₂ are vapour pressure of water and of liquid at the distillation temperature and M is the molecular mass of the liquid.

Question 9.
Dehydrobromination of compounds (A) and (B) yield the same alkene (c) Alkene (c) Can regenerate (A) and (B) by the addition of HBr in the presence and absence of peroxide respectively. Hydrolysis of A and B give isomeric products (D) and (E) respectively. 1, 1-Diphenyl ethane is obtained on the reaction of (C) of benzene in the presence of H⁺ ions. Give structures of A to E with reactions.

Answer:
Alkene (C) on reaction with benzene in the presence of H+ ions gives 1, 1-Diphenyl ethane. Therefore C must be styrene as depicted below

Now dehydrobromination of A and B give the same alkene C, i.e.,
styrene.
∴ A and B must be isomeric alkyl bromide.

A and B can be obtained by the addition of HBr in the presence and absence of peroxide to styrene.

Hydrolysis of A and B give isomeric alcohols (D) & (E) as

Question 10.
What are reaction intermediates? How are they generated by bond fission?

Answer:
The species which are generated as a result of bond fission are called reaction intermediates. The important reaction intermediates are:
1. Free Radicals: A free radical may be defined as an atom or group of atoms having an impaired electron. These are obtained as a result of homolytic fission of covalent bonds.

These free radicals are neutral particles, extremely transient, (short-lived) and highly reactive. They get consumed as soon as they are formed. They pair up their electron with another electron from wherever it is available. They occur only as a reaction intermediate. Their presence is felt in reactions, but cannot be isolated in a free state. For example dissociation of Cl2 gas in the presence of Ultraviolet light produces free radicals.

The alkyl free radicals are obtained when free radical: Cl reacts with alkanes.

Free radical may be primary, secondary, tertiary depending upon whether, one, two or three carbon atom attached to the carbon atoms carrying the odd electron.

The stability is CH₃ < 1° < 2° < 3°.

2. Carbocation or carbonium ion: It is defined as a group of atoms that contain positively charged carbon having only six electrons. It is obtained by heterolytic fission of a covalent bond involving a carbon atom.

They are also classified as primary, secondary and tertiary depending upon whether one, two or three carbon atoms are attached to the carbon bearing the positive charge as:

Thus the order of stability if CH₃⁺ < 1° < 2° < 3°.

3. Carbanion: A carbanion may be defined as a species containing a carbon atom carrying a negative charge. These are generated by the atom in which the atom linked to carbon goes without the bonding electrons. As a result of this carbon acquires a negative charge. For example, the removal of hydrogen of methyl part of acetaldehyde molecule as H+ ion leaving both the electron on carbon.

They are also very reactive species. They are also classified as primary, secondary and tertiary depending upon whether one, two or three carbon atoms are attached to the carbon atom bearing negative
charge.

The order of stability is the reverse of free radicals and carbocations
CH₃ ^– > 1° > 2° > 3°.

(iv) Carbenes: The carbenes are reactive neutral species in which carbon atom has six electrons in the valency shell out of which two are shared. The simplest carbene is methylene (CH₂). It is formed when diazomethane is decomposed by the action of light.

It is very reactive. It reacts with alkenes by adding to the double bond forming cyclopropane.