To perform the reaction of Iron nails kept in copper sulphate solution and classify it on Combination reaction, Decomposition reaction, Displacement reaction and Double displacement reaction
Aim
To perform the reaction of Iron nails kept in copper sulphate solution and classify it on:i. Combination reaction
ii. Decomposition reaction
iii. Displacement reaction
iv. Double displacement reaction
Theory
(a) Iron is more reactive than sulphur.
(b) When iron is added to the aqueous solution of a copper salt, iron displaces copper.
Reaction: Fe(s) + CuSO4(aq) → FeSO4(s) + Cu(s)
Fe(s) + Cu2+(aq) → Fe2+(aq) + Cu(s)
Copper ion(Blue) Ferrous ion(Light green)
(c) Due to this displacement reaction, the solution which was originally sky blue in colour, turns light green and the iron article is covered with a reddish brown layer of copper.
Chemicals Required
Copper sulphate solution
Apparatus Required
Test tube holder, Test tubes, Iron nails, Sand paper
Procedure
Step 1: Two iron nails are taken and rubbed with a sand paper to make them shining.
Step 2: 10 ml of copper sulphate solution is taken in two separate test tubes.
Step 3: One of the iron nail is placed in one test tube. Other iron nail and test tube containing copper sulphate solution are kept for comparison.
Step 4: The test tube containing iron nail in copper sulphate solution is kept for about 40 minutes.
Step 5: Observations are recorded.
Observation Table
| Sl. No. | Experiment | Observation | Inference |
| 1. | Original colour of the solution is noted. | Sky blue | The solution contains Cu2+ ions. |
| 2. | Original colour of the iron nail is noted. | Steel grey | The nail has the natural colour of the iron. |
| 3. | Colour of the solution after the experiment is noted. | Light green | The solution contains Fe2+ ions. |
| 4. | Colour of the iron nail after the experiment is noted. | Reddish brown | The iron is covered with thin layer of copper. |
Result
1. The brown coating on the iron nail shows that copper is deposited on the iron nail by displacing iron.
2. The greenish colour of the solution in the test tube shows that Fe2+ ions are present in the solution.
3. This shows that iron is more reactive than copper, as Fe2+ ions have displaced Cu2+ ions from copper sulphate solution.
4. This is a single displacement reaction in which copper has been displaced from iron from copper sulphate solution.
Reaction: Fe(s) + CuSO4(aq) → FeSO4(s) + Cu(s)
Precautions
1. Clean the iron nails by rubbing with sand paper to remove rust, dust or greasy surface.
2. Keep the control experiment to compare the colour of iron nails and copper sulphate solution.
3. Avoid touching copper sulphate solution or nail dipped in copper sulphate solution as copper sulphate is poisonous.
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