Question

Iron nails were dipped in a solution kept in a test tube. After half an hour, it was observed that the colour of the solution has changed. The solution present in the test tube before the reaction was that of:

• A. Zinc sulphate
• B. Copper sulphate
• C. Iron sulphate
• D. Aluminium sulphate

Answer 1

The correct option is B Copper sulphate

Iron is more reactive than copper but less reactive than zinc and aluminium.
Hence, it will displace copper from copper sulphate solution and not zinc and aluminium from their respective solution.

The reaction will occur as follows:

$\underset{\text{(Blue)}}{{\text{CuSO}}_4\text{(aq)}}+\text{Fe(s)}\to \underset{\text{(Green)}}{{\text{FeSO}}_4\text{(aq)}}+\text{Cu(s)}$

So, the solution present in the test tube was copper sulphate.