Chapter 2: Exploring Substances: Acidic, Basic, and Neutral Class 8th Science (Curiosity) NCERT Solution

July 13, 2026 • Admin ETeam • Class 7, Class 7 NCERT Solution

Class 7 Science Chapter 2 – Exploring Substances: Acidic, Basic and Neutral | Solutions

Curiosity • Textbook of Science • Grade 7

Chapter 2 — Exploring Substances: Acidic, Basic, and Neutral

All activities, tables, in-text questions and the complete “Let Us Enhance Our Learning” exercise — solved with the chapter’s own figures.

In-Text Questions, Activities & Tables

Scene of a science fair on National Science Day — Fig. 2.1 — Scene of a science fair (from the chapter)

The chapter’s opening puzzle: Ashwin and Keerthi were given a plain white sheet, a liquid was sprayed on it, and the words “Welcome to the Wonderful World of Science” appeared. Keep this in mind — the answer is given at the end of this section (Wrap Up).

2.1.1 Litmus as an indicator — Activity 2.1 (Let us explore)

Girl putting drops of samples on blue litmus pieces — Fig. 2.2(a) — Colour change in blue litmus paper (from the chapter)

Boy putting drops of samples on red litmus pieces — Fig. 2.2(b) — Colour change in red litmus paper (from the chapter)

A2.1

Do you observe any change in the colour of the litmus pieces? Record your observations in Table 2.1.

SOLUTION — TABLE 2.1 (COMPLETED)

S.No.	Name of the sample	Colour of blue litmus after a drop	Colour of red litmus after a drop	Nature
1	Lemon juice	Turns red	No change (stays red)	Acidic
2	Soap solution	No change (stays blue)	Turns blue	Basic
3	Amla juice	Turns red	No change	Acidic
4	Tamarind water	Turns red	No change	Acidic
5	Vinegar	Turns red	No change	Acidic
6	Baking soda solution	No change	Turns blue	Basic
7	Lime water	No change	Turns blue	Basic
8	Tap water	No change	No change	Neutral
9	Washing powder solution	No change	Turns blue	Basic
10	Sugar solution	No change	No change	Neutral
11	Salt solution	No change	No change	Neutral
12	Any other — e.g. curd	Turns red	No change	Acidic

Table 2.2 — Grouping of the samples

Group A (turn blue litmus red)	Group B (turn red litmus blue)	Group C (no effect on either)
Lemon juice, Amla juice, Tamarind water, Vinegar, (Curd)	Soap solution, Baking soda solution, Lime water, Washing powder solution	Tap water, Sugar solution, Salt solution
→ ACIDIC	→ BASIC	→ NEUTRAL

Conclusion: Group A substances are acidic, Group B are basic, and Group C are neutral (neither acidic nor basic).

What are these red and blue litmus paper strips made of? Why do they change colour when drops of some samples are put on them?

SOLUTION

Fig. 2.3 — Blue and red litmus paper strips (from the chapter)

Litmus is a natural substance obtained from lichens.
It is available both as a solution and as paper strips (litmus paper), in two colours — blue and red.
It changes colour because it shows different colours in acidic and basic solutions: it turns red in acids and blue in bases.
Because of this property it is called an acid-base indicator.

Lichens growing on a tree — Fig. — Lichens: a fungus and an alga living together (from the chapter)

Holistic Lens: Lichens are formed by the association of two living organisms — a fungus and an alga. They grow on rocks and trees where there is abundant rainfall and clean air. So lichens on neighbourhood trees are a sign of clean air.

Activity 2.2 — Let us relate and explore

A2.2

Are all the substances in Group A edible? What is their taste? Find out and write the names of the most common acids present in — Lemon ____, Curd ____, Tamarind ____, Vinegar ____.

SOLUTION

Not all Group A substances are edible, but the edible ones (lemon juice, amla juice, tamarind water, vinegar, curd) all taste sour. Hence, substances that taste sour tend to contain acids and are acidic in nature.

⚠ Caution (as given in the book): Do not taste anything until asked to do so, and never taste an unknown substance.

Common acids present in orange, amla, tamarind and tomato — Fig. 2.4 — The most common acids present in some edible substances (from the chapter)

Substance	Most common acid present
Orange	Citric acid
Amla	Ascorbic acid (Vitamin C) and Citric acid
Tamarind	Tartaric acid
Tomato	Citric acid and Oxalic acid
Lemon	Citric acid
Curd	Lactic acid
Vinegar	Acetic acid

Rubbing the baking soda solution between the fingers — what do you observe?

It feels soapy / slippery. Basic substances are generally slippery to touch.
Bases generally taste bitter — but everything bitter is not basic. For example, bitter gourd (karela) tastes bitter yet is not basic in nature.

2.1.2 Red rose as an indicator — Activities 2.3 & 2.4

If litmus is not available, are there other natural substances that can serve as acid-base indicators? How is the red rose extract prepared? (Activity 2.3)

SOLUTION

Yes. Many natural substances act as indicators — red rose petals, red hibiscus (gudhal), purple cabbage, beetroot, turmeric, Indian blackberry (jamun), etc.

Preparation of red rose extract — step by step

Step 1. Collect fallen petals of red roses. (Do not pluck flowers — pick only petals or flowers fallen on the ground.)

Step 2. Take a fistful of petals and wash them with water.

Step 3. Crush the petals with a mortar and pestle and place them in a glass tumbler.

Step 4. Pour hot water so that the crushed petals are completely immersed. (Do this under the supervision of an adult.)

Step 5. Cover the tumbler with a lid and wait 5–10 minutes till the water becomes coloured.

Step 6. Filter it. The filtrate (liquid after filtration) is the required flower extract — the acid-base indicator.

Red rose petals immersed in hot water in a glass tumbler — Fig. 2.6 — Red rose petals immersed in hot water (from the chapter)

Test tube in a test tube stand containing red rose extract — Fig. 2.7 — Test tube containing the red rose extract (from the chapter)

A2.4

Add lemon juice to test tube A and soap solution to test tube B (each containing red rose extract). Record the colour changes in Table 2.3.

SOLUTION — TABLE 2.3 (COMPLETED)

Test tubes A and B showing red and green colour of red rose extract — Fig. 2.8 — Colour change of the red rose extract on adding lemon juice (A) and soap solution (B) (from the chapter)

S.No.	Name of the sample	Colour of the red rose extract after adding the sample	Nature of the substance
1	Lemon juice	Turns a shade of red	Acidic
2	Soap solution	Turns a shade of green	Basic
3	Amla juice	Red	Acidic
4	Tamarind water / Vinegar	Red	Acidic
5	Baking soda solution / Lime water / Washing powder solution	Green	Basic
6	Tap water / Sugar solution / Salt solution	No change	Neutral

The three discussion questions

Are the samples that turn the extract red the same as those that turned blue litmus red (Group A)? — Yes. Both tests identify the same acidic substances.
Are the samples that turn the extract green the same as those that turned red litmus blue (Group B)? — Yes. Both identify the same basic substances.
Are the samples that do not change the extract the same as those that did not change either litmus (Group C)? — Yes. These are the neutral substances.

Conclusion: Red rose extract is also an acid-base indicator. It gives red colour in an acidic solution and green colour in a basic solution, and shows no change with neutral substances.

Fascinating Facts: Can gardeners alter the colour of hydrangea flowers by adjusting the acidic or basic nature of the soil?

SOLUTION

Blue and pink hydrangea flowers — Fig. — Hydrangea flowers (from the chapter)

Yes. The hydrangea plant behaves like a living indicator:

Acidic soil → blue-coloured flowers.
Basic soil → pink or red flowers.

So a gardener can make the soil more acidic (to get blue flowers) or more basic — for example by adding lime, a base (to get pink/red flowers) — and thus change the colour of the flowers.

2.1.3 Turmeric as an indicator — Activity 2.5

A2.5

Prepare turmeric paper and test all the samples of Activity 2.1. Record in Table 2.4. Do all samples change the colour of the turmeric paper? Can turmeric paper be used as an indicator for acidic substances?

SOLUTION

Turmeric paste in a petri dish and turmeric paper strips — Fig. 2.9 — (a) Turmeric paste and (b) Turmeric paper strips (from the chapter)

Preparation (step by step)

Step 1. Take a spoonful of turmeric (haldi) in a petri dish and add a little water to make a paste.

Step 2. Dip a piece of filter paper in the paste until it becomes yellow.

Step 3. Take it out and let it dry.

Step 4. Cut the yellow paper into thin strips — this is turmeric paper.

Table 2.4 — Completed

S.No.	Name of the sample	Colour of the turmeric paper after a drop	Nature
1	Lemon juice	No change (stays yellow)	Acidic
2	Soap solution	Turns red	Basic
3	Amla juice	No change (yellow)	Acidic
4	Tamarind water, Vinegar	No change (yellow)	Acidic
5	Baking soda solution, Lime water, Washing powder solution	Turns red	Basic
6	Tap water, Sugar solution, Salt solution	No change (yellow)	Neutral

Answers to the questions

Do all samples change the colour? — No. Only the basic samples turn the yellow turmeric paper red.
Samples that do not change the colour: all of Group A (acidic) and all of Group C (neutral).
Can turmeric paper be used as an indicator for acidic substances? — No. Turmeric paper can be used to test basic substances, but it cannot differentiate between acidic and neutral substances, because both leave it unchanged.

Turmeric root and turmeric powder — Fig. — Turmeric (*haldi*), the ‘golden’ spice of the ginger family (from the chapter)

Why does the curry stain on a white shirt turn red on applying soap? Curry contains turmeric. Soap is basic, so it turns the yellow turmeric stain red — the shirt itself is acting as turmeric paper!

Ashwin applied turmeric paste on white paper, dried it, and wrote his Guru Purnima wishes on it using one of the solutions of Table 2.4. Which solution can be used to write the message?

SOLUTION

Guru Purnima greeting card written on turmeric paper — Fig. — Ashwin’s greeting card written on turmeric paper (from the chapter)

He must use a basic solution — such as soap solution (or baking soda solution / lime water / washing powder solution).

Reason

The dried paper is coated with yellow turmeric.
A base turns turmeric red. So the letters written with the soap solution appear in red on the yellow background — a clearly visible message.
An acidic or a neutral solution would leave the paper yellow, so nothing would be seen.

Olfactory indicators — Activity 2.6

A2.6

Are there substances whose odour changes on adding acidic or basic substances? What do you observe with the onion strips?

SOLUTION

Yes. Substances whose odour changes in an acidic or a basic medium are called olfactory indicators (from olfaction = sense of smell).

Observations of the activity

Before adding anything: both cotton/filter-paper strips kept overnight with chopped onions have a strong onion smell.

Strip + tamarind water (acidic): the onion smell remains (it can still be detected).

Strip + baking soda solution (basic): the onion smell disappears / becomes very faint.

Conclusion: Onion is an olfactory indicator — its odour is destroyed by a base but not by an acid. Other examples: vanilla extract and clove oil. Such indicators are especially useful for visually impaired students.

2.2 What happens when acidic substances mix with basic substances? — Activity 2.7

A2.7

Lemon juice + water + a drop of blue litmus solution, then lime water added drop by drop, then one more drop of lemon juice. Can you predict why there is a change in colour?

SOLUTION

Step 1 – Blue litmus added to the dilute lemon juice. The solution turns red, because lemon juice is an acid [Fig. 2.10(a)].

Step 2 – Lime water is added drop by drop. Lime water is a base. It slowly cancels the effect of the acid.

Step 3 – A stage comes when the colour changes from red to blue [Fig. 2.10(b)]. This shows the solution is no longer acidic — the lime water has neutralised the acid, and further addition has made it basic.

Step 4 – One more drop of lemon juice is added. The solution turns red again, because it becomes acidic once more.

Neutralisation

When the solution of an acid is mixed with the solution of a base in sufficient quantity, the resulting solution is neither acidic nor basic. Such a reaction is called a neutralisation reaction. In it, salt and water are formed with the evolution (release) of heat:

Acid + Base → Salt + Water + Heat

2.3 Neutralisation in daily life — Situations 1, 2 and 3

Situation 1: A red ant bit Keerthi, leaving her skin red with stinging pain. Her brother applied moist baking soda, which relieved the pain. What might be the reason? What remedies do people use for ant bites in your region?

SOLUTION

A girl bitten by a red ant near a tree — Fig. 2.11 — Stinging effect of an ant bite (from the chapter)

When an ant bites, it injects an acidic liquid — formic acid — into the skin, which causes the burning pain.
Baking soda is a base. Rubbing moist baking soda on the spot neutralises the acid, so the pain is relieved.

Other common remedies: applying calamine lotion (which contains zinc carbonate, a base), lime (chuna), or a paste of baking soda and water.

Situation 2: A farmer’s plants are not growing well; excessive use of chemical fertilisers has made the soil acidic. What remedy might be provided? And what if the soil is basic?

SOLUTION

A farmer spreading lime to neutralise acidic soil — Fig. 2.12 — Neutralising the acidic nature of soil (from the chapter)

Nature of soil	Treatment	Why it works
Too acidic	Add lime (chuna) / quick lime / slaked lime	Lime is a base; it neutralises the excess acid.
Too basic	Add organic matter — manure, composted leaves	Organic matter releases acids that neutralise the basic nature.
Neutral but plants still unhealthy	Add the missing nutrients	Poor health may be due to a deficiency of nutrients in the soil, not its acidity.

Situation 3: The fish population in a lake near an industrial area is declining. What might be the cause? If the factory waste is acidic, what could be done to save the fish?

SOLUTION

Probable cause: factory waste being released into the lake, which makes the lake water acidic and harmful for fish.
Remedy: the factory waste should be neutralised by adding basic substances before it is released into the lake.

This shows the responsibility side of science — the same neutralisation reaction that soothes an ant bite can save an entire lake.

Let us wrap up! Why did the words ‘Welcome to the Wonderful World of Science’ appear on Ashwin and Keerthi’s white paper sheets when the liquid was sprayed on them?

SOLUTION

Step 1. The words were written on the white paper beforehand with a soap solution (a base) — being colourless when dry, the writing was invisible.

Step 2. The spray bottle contained a turmeric solution (an indicator).

Step 3. When sprayed, the turmeric touched the basic writing. A base turns turmeric red.

Step 4. So the message appeared instantly in red letters on the yellowish paper — a neat acid–base indicator trick, not magic!

Let Us Enhance Our Learning (Exercise)

A solution turns the red litmus paper to blue. Excess addition of which of the following solutions would reverse the change?
(i) Lime water (ii) Baking soda (iii) Vinegar (iv) Common salt solution

SOLUTION

Answer: (iii) Vinegar

Explanation

The given solution turns red litmus blue → it is basic.
To reverse the change (make the litmus red again), we must make the solution acidic. That needs an acid in excess.
Vinegar (acetic acid) is the only acid in the list.

Lime water and baking soda are bases (they would strengthen the blue), and common salt solution is neutral (no effect at all).

Solution A turns red litmus blue; turmeric turns red in solution B; red rose extract turns green in solution C. Which is the correct sequence for A, B and C?
(i) Acidic, acidic, acidic (ii) Neutral, basic, basic (iii) Basic, basic, acidic (iv) Basic, basic, basic

SOLUTION

Answer: (iv) Basic, basic, and basic

Solution	Indicator & observation	Rule	Nature
A	Red litmus → blue	Bases turn red litmus blue	Basic
B	Turmeric → red	Turmeric turns red only in bases	Basic
C	Red rose extract → green	Rose extract is green in bases (red in acids)	Basic

All three indicators point to the same nature — the three solutions are all basic.

Observe and analyse Figs. 2.13, 2.14 and 2.15, in which red rose extract paper strips are used. Label the nature of the solutions present in each container.

SOLUTION

Red rose extract strip turning green — Fig. 2.13 — the strip turns **green**

Red rose extract strip showing no change — Fig. 2.14 — the strip shows **no change**

Red rose extract strip turning red — Fig. 2.15 — the strip turns **red**

Figure	Colour of the rose-extract strip	Nature of the solution
Fig. 2.13	Turns green	Basic
Fig. 2.14	No change in colour	Neutral
Fig. 2.15	Turns red	Acidic

Rule used: Red rose extract → red in acidic, green in basic, unchanged in neutral solutions.

A liquid was tested: red litmus – no change; blue litmus – turned red; turmeric – no change in colour. Identify the nature of the liquid and justify.

SOLUTION

The liquid is ACIDIC in nature.

Indicator	Observation	What it proves
Blue litmus	Turned red	Only an acid turns blue litmus red → decisive proof
Red litmus	No change	It is not basic (a base would have turned it blue)
Turmeric	No change (stays yellow)	Again not basic; turmeric cannot separate acidic from neutral

Justification: The turmeric and red-litmus tests only rule out a base. It is the blue litmus turning red that confirms the liquid is an acid (e.g. lemon juice or vinegar).

Manya is blindfolded. She is given two unknown solutions and must decide whether they are acidic or basic. Which indicator should she use and why?

SOLUTION

She should use an olfactory indicator — for example onion strips (or vanilla extract, or clove oil).

Why

Being blindfolded, Manya cannot see any colour change, so litmus, turmeric and red rose extract are of no use to her.
An olfactory indicator changes its odour in acidic and basic media — and odour can be smelled, not seen.
How to use it: put a few drops of each solution on separate onion-treated strips.
- Strip on which the onion smell disappears → the solution is basic.
- Strip on which the onion smell remains → the solution is acidic.

This is exactly why olfactory indicators are so valuable for visually impaired learners.

Suggest various materials which can be used for writing the message on the white sheet and what could be in the spray bottle. Make a table of possible combinations and the colour of the writing obtained.

SOLUTION

The trick needs two things: an invisible writing liquid (an acid or a base) and a spray of an indicator that changes colour with it.

#	Written on the paper with	Sprayed from the bottle	Colour of the writing that appears
1	Soap solution (base)	Turmeric solution	Red writing on yellow paper
2	Baking soda solution (base)	Turmeric solution	Red writing
3	Lime water / Washing powder solution (base)	Turmeric solution	Red writing
4	Baking soda solution (base)	Red rose extract	Green writing
5	Lemon juice / Vinegar (acid)	Red rose extract	Red writing
6	Soap solution (base)	Red litmus solution	Blue writing
7	Lemon juice (acid)	Blue litmus solution	Red writing

Combination #1 is the one used at the science fair in Fig. 2.1 — the paper is sprayed with turmeric solution and the message was written with a soap solution.

Grape juice was mixed with red rose extract; the mixture got a tint of red. What will happen if baking soda is added to this mixture? Justify.

SOLUTION

Step 1 – What the red tint tells us. Red rose extract gives red in acidic solutions. So grape juice is acidic (it contains tartaric acid).

Step 2 – What baking soda is. Baking soda solution is basic.

Step 3 – What happens on adding it. The base first neutralises the acid of the grape juice (Acid + Base → Salt + Water + Heat). On adding it in sufficient/excess quantity, the mixture becomes basic.

Step 4 – Observation. The red rose extract therefore changes from red to green.

Answer: The colour of the mixture will change to green, showing that the solution has become basic.

Keerthi wrote a secret message using orange juice. Which indicator would you use to make it visible?

SOLUTION

Step 1. Orange juice contains citric acid → the writing liquid is acidic.

Step 2. So we need an indicator that changes colour in an acid.

Step 3 – Best choice: spray blue litmus solution on the paper → the message appears in red.
Another good choice: spray red rose extract (or China rose / purple cabbage extract) → the message appears in a shade of red.

Do NOT use turmeric. Turmeric does not change colour with acids — the message would stay invisible.

How can natural indicators be prepared? Explain by giving an example.

SOLUTION

Natural indicators are prepared as an extract of a coloured flower, vegetable or spice.

Example — Red rose extract (Activity 2.3)

1. Collect fallen petals of red roses and wash them with water.

2. Crush them using a mortar and pestle and put them in a glass tumbler.

3. Pour hot water until the petals are fully immersed (with an adult’s help).

4. Cover and wait 5–10 minutes till the water becomes coloured.

5. Filter it — the filtrate is the natural indicator.

6. Test: it turns red with acids and green with bases.

Fig. 2.6 — Petals immersed in hot water (from the chapter)

Another example — Turmeric paper (Activity 2.5)

Make a paste of turmeric with a little water, dip filter paper in it, dry it, and cut it into strips. It turns red in basic solutions.

Other natural indicators: purple cabbage, beetroot, jamun, red hibiscus (gudhal), lichen (litmus).

Q10

Three liquids: vinegar, baking soda solution, sugar solution. Can you identify them only using turmeric paper? Explain.

SOLUTION

No — not completely. Turmeric paper can identify only one of the three.

Liquid	Nature	Effect on turmeric paper	Can it be identified?
Baking soda solution	Basic	Turns red	✔ Yes
Vinegar	Acidic	No change (yellow)	✘ No
Sugar solution	Neutral	No change (yellow)	✘ No

Explanation

Turmeric cannot differentiate between an acidic and a neutral substance — both leave it yellow. So vinegar and sugar solution give identical results.

How to complete the identification: use blue litmus paper on the remaining two. The one that turns it red is vinegar; the one that causes no change is the sugar solution.

Q11

The extract of red rose turns liquid X to green. What will the nature of X be? What will happen when excess of amla juice is added to X?

SOLUTION

Step 1 – Nature of X. Red rose extract gives green only in a basic solution. → X is BASIC in nature.

Step 2 – What is amla juice? It contains ascorbic acid (Vitamin C) and citric acid → it is acidic.

Step 3 – On adding it. Acid + Base → neutralisation (salt + water + heat). First the mixture becomes neutral; with excess amla juice it becomes acidic.

Step 4 – Observation. The colour changes from green → (no colour / neutral) → red.

Answer: X is basic; with excess amla juice it is neutralised and finally turns red, showing that the solution has become acidic.

Q12

Complete the missing information in the flowchart about a garden with plants showing signs of poor health.

SOLUTION

Fig. — The completed flowchart (Q12)

Blank	Correct answer
The soil can be ____ in nature. (left)	Acidic
The soil can be ____ in nature. (right)	Basic
Which indicator can be used to test the soil?	Litmus paper (red and blue) — turmeric paper or red rose extract can also be used
The acidic soil can be treated with ____	Lime (chuna) — a base
The basic soil can be treated with ____	Organic matter — manure / composted leaves

Note: if the soil is neutral and the plants are still unhealthy, the problem is a deficiency of nutrients, not acidity.

Dive Deeper: Aman spilt vinegar on pieces of eggshell/marble and noticed bubbling. With a soap solution on another piece, no bubbles appeared. Why?

SOLUTION

Step 1 – What eggshell and marble are made of. Both are made mainly of calcium carbonate.

Step 2 – Vinegar is an acid (acetic acid). An acid reacts with a carbonate and a gas — carbon dioxide — is released. The escaping gas is seen as bubbling / effervescence.
Carbonate + Acid → Salt + Water + Carbon dioxide (gas)

Step 3 – Soap solution is a base. A base does not react with calcium carbonate, so no gas is produced and hence no bubbles appear.

Conclusion: The bubbling is a test for an acid acting on a carbonate. This is also why acidic rain/acids slowly damage marble monuments.

Exploratory Projects — how to do them.

GUIDANCE

Rangoli with indicators: draw the design on paper/cloth with turmeric solution (yellow). Then, using a brush, paint parts of it with a soap or baking soda solution — those parts instantly turn red. Use red rose or beetroot extract for pink/green shades to get more colours.
Water from various sources: test rain water, tap water and river water with red and blue litmus. Tap water is usually neutral; rain water can be slightly acidic; river water near industry may be acidic or basic. Record and compare in a table.
Soil of your area: shake a soil sample with distilled water, let it settle, and test the clear liquid with red and blue litmus. Blue → red means acidic soil (treat with lime); red → blue means basic soil (add manure/compost); no change means neutral.

Q+

Extra numerical practice: In Activity 2.7 a student takes 1 drop of lemon juice and adds 20 drops of water. If 1 drop = 0.05 mL, find (a) the total volume of the solution, and (b) the fraction of lemon juice in it.

SOLUTION

Step 1 – Given. Volume of one drop, $v = 0.05\ \text{mL}$; lemon juice = 1 drop; water = 20 drops.

Step 2 – Volume of each part. $$V_{\text{lemon}} = 1 \times 0.05 = 0.05\ \text{mL}$$ $$V_{\text{water}} = 20 \times 0.05 = 1.0\ \text{mL}$$

Step 3 – (a) Total volume. $$V_{\text{total}} = 0.05 + 1.0 = \mathbf{1.05\ \text{mL}}$$

Step 4 – (b) Fraction of lemon juice. $$f = \frac{V_{\text{lemon}}}{V_{\text{total}}} = \frac{0.05}{1.05} = \frac{1}{21} \approx 0.048 = \mathbf{4.8\%}$$

This is why the acid is called a dilute solution — less than 5% of it is lemon juice, yet it is still acidic enough to turn blue litmus red.

Chapter 2: Exploring Substances: Acidic, Basic, and Neutral Class 8th Science (Curiosity) NCERT Solution

Chapter 2 — Exploring Substances: Acidic, Basic, and Neutral

Table 2.2 — Grouping of the samples

Rubbing the baking soda solution between the fingers — what do you observe?

Preparation of red rose extract — step by step

The three discussion questions

Preparation (step by step)

Table 2.4 — Completed

Answers to the questions

Reason

Observations of the activity

Neutralisation

Explanation

Why

Example — Red rose extract (Activity 2.3)

Another example — Turmeric paper (Activity 2.5)

Explanation

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