CLASS 10 CBSE CHEMISTRY PRACTICAL

EXPERIMENT: Observing the Action of Zn, Fe, Cu and Al Metals on Salt Solutions and Arranging them in Decreasing Order of Reactivity

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AIM:

1. To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions:

• ZnSO₄ (aq)
• FeSO₄ (aq)
• CuSO₄ (aq)
• Al₂(SO₄)₃ (aq)

1. To arrange Zn, Fe, Cu and Al (metals) in the decreasing order of reactivity based on the above results.

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MATERIALS REQUIRED:

1. Test tubes (16)
2. Test tube stand
3. Test tube holder
4. Sandpaper/emery paper
5. Zinc (Zn) granules/strips
6. Iron (Fe) nails/strips
7. Copper (Cu) strips/turnings
8. Aluminium (Al) strips/foils
9. Zinc sulphate solution (ZnSO₄)
10. Ferrous sulphate solution (FeSO₄)
11. Copper sulphate solution (CuSO₄)
12. Aluminium sulphate solution [Al₂(SO₄)₃]
13. Dropper
14. Distilled water

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THEORY:

Reactivity Series:
The reactivity series is an arrangement of metals in decreasing order of their reactivity. A more reactive metal can displace a less reactive metal from its salt solution.

Displacement Reaction:
When a more reactive metal is placed in the salt solution of a less reactive metal, the more reactive metal displaces the less reactive metal from its salt solution.

General Reaction:

A (more reactive metal) + B-Salt → A-Salt + B (less reactive metal)

Expected Reactivity Order:

Al > Zn > Fe > Cu
(Most reactive)        (Least reactive)

Principle:

• If a metal displaces another metal from its salt solution, the displacing metal is more reactive.
• If no displacement occurs, the metal in the solution is more reactive than the metal added.
• A metal cannot displace itself from its own salt solution.

Observations Expected:

• Reaction occurs: Change in color of solution, deposition of metal on the strip, temperature change
• No reaction: No visible change

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PROCEDURE:

1. Clean all metal strips (Zn, Fe, Cu, Al) with sandpaper to remove any oxide layer or impurities.
2. Take 16 clean and dry test tubes and arrange them in 4 sets (labeled A, B, C, D) with 4 test tubes in each set.
3. Set A: Pour about 5 mL of ZnSO₄ solution in each of the 4 test tubes labeled A1, A2, A3, A4.
4. Set B: Pour about 5 mL of FeSO₄ solution in each of the 4 test tubes labeled B1, B2, B3, B4.
5. Set C: Pour about 5 mL of CuSO₄ solution in each of the 4 test tubes labeled C1, C2, C3, C4.
6. Set D: Pour about 5 mL of Al₂(SO₄)₃ solution in each of the 4 test tubes labeled D1, D2, D3, D4.
7. Add the metals to respective test tubes as follows:

• To test tubes A1, B1, C1, D1 → Add Zn strip
• To test tubes A2, B2, C2, D2 → Add Fe nail/strip
• To test tubes A3, B3, C3, D3 → Add Cu strip
• To test tubes A4, B4, C4, D4 → Add Al strip

1. Keep all test tubes undisturbed for about 20-30 minutes.
2. Observe carefully for:

• Change in color of solution
• Deposition of metal on the strip
• Dissolution of the metal strip
• Any other visible change

1. Record your observations in the observation table.

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OBSERVATION:

Observation Table:

Test Tube	Salt Solution	Metal Added	Observation	Reaction/No Reaction	Inference
A1	ZnSO₄	Zn	No visible change	No Reaction	Metal cannot displace itself
A2	ZnSO₄	Fe	No visible change	No Reaction	Fe is less reactive than Zn
A3	ZnSO₄	Cu	No visible change	No Reaction	Cu is less reactive than Zn
A4	ZnSO₄	Al	Colorless solution remains same, Al strip dissolves slightly	Reaction occurs	Al is more reactive than Zn
B1	FeSO₄	Zn	Light green solution fades, greyish deposit on Zn	Reaction occurs	Zn is more reactive than Fe
B2	FeSO₄	Fe	No visible change	No Reaction	Metal cannot displace itself
B3	FeSO₄	Cu	No visible change	No Reaction	Cu is less reactive than Fe
B4	FeSO₄	Al	Solution color changes, Al strip dissolves, greyish deposit	Reaction occurs	Al is more reactive than Fe
C1	CuSO₄	Zn	Blue color fades, reddish-brown Cu deposits on Zn	Reaction occurs	Zn is more reactive than Cu
C2	CuSO₄	Fe	Blue color fades to light green, reddish-brown Cu deposits on Fe	Reaction occurs	Fe is more reactive than Cu
C3	CuSO₄	Cu	No visible change	No Reaction	Metal cannot displace itself
C4	CuSO₄	Al	Blue color fades, reddish-brown Cu deposits on Al	Reaction occurs	Al is more reactive than Cu
D1	Al₂(SO₄)₃	Zn	No visible change	No Reaction	Zn is less reactive than Al
D2	Al₂(SO₄)₃	Fe	No visible change	No Reaction	Fe is less reactive than Al
D3	Al₂(SO₄)₃	Cu	No visible change	No Reaction	Cu is less reactive than Al
D4	Al₂(SO₄)₃	Al	No visible change	No Reaction	Metal cannot displace itself

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CHEMICAL EQUATIONS:

Reactions that occur:

1. Zn + FeSO₄ → ZnSO₄ + Fe
   (Zinc displaces iron)
2. Zn + CuSO₄ → ZnSO₄ + Cu
   (Zinc displaces copper)
3. Fe + CuSO₄ → FeSO₄ + Cu
   (Iron displaces copper)
4. 2Al + 3ZnSO₄ → Al₂(SO₄)₃ + 3Zn
   (Aluminium displaces zinc)
5. 2Al + 3FeSO₄ → Al₂(SO₄)₃ + 3Fe
   (Aluminium displaces iron)
6. 2Al + 3CuSO₄ → Al₂(SO₄)₃ + 3Cu
   (Aluminium displaces copper)

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REACTIVITY ANALYSIS:

Based on displacement reactions:

Metal	Can Displace	Cannot Displace
Al	Zn, Fe, Cu	None (most reactive)
Zn	Fe, Cu	Al
Fe	Cu	Al, Zn
Cu	None (least reactive)	Al, Zn, Fe

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RESULT:

1. Aluminium (Al) displaced Zn, Fe, and Cu from their salt solutions.
2. Zinc (Zn) displaced Fe and Cu from their salt solutions but not Al.
3. Iron (Fe) displaced only Cu from its salt solution.
4. Copper (Cu) did not displace any metal from their salt solutions.

Decreasing Order of Reactivity:

Al > Zn > Fe > Cu
(Most Reactive)  →  (Least Reactive)

Therefore, the arrangement of metals in decreasing order of reactivity is:
Aluminium > Zinc > Iron > Copper

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PRECAUTIONS:

1. Clean all metal strips thoroughly with sandpaper before use to remove oxide layer.
2. Use dilute salt solutions for better and safe results.
3. Keep the test tubes undisturbed for sufficient time (20-30 minutes) to observe reactions clearly.
4. Use equal amounts of solutions and similar-sized metal pieces for fair comparison.
5. Handle all chemicals carefully and avoid direct contact with skin.
6. Some reactions may be slow; be patient and observe carefully.
7. Do not taste or smell any chemical directly.
8. Label all test tubes properly to avoid confusion.
9. Aluminium reacts slowly initially due to its protective oxide layer; wait longer for visible changes.
10. Perform the experiment in a well-ventilated area.
11. Wear safety goggles if available.
12. Dispose of chemicals as per laboratory guidelines.
13. Clean all apparatus after use.
14. Wash hands thoroughly after completing the experiment.

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Signature of Teacher: ___