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

$\bullet$ Iron is more reactive than copper but less reactive than zinc and aluminium.

$\bullet$ Hence, it will displace copper from copper sulphate solution and not zinc and aluminium from their respective solution.

$\bullet$ The reaction will occur as follows:
$\underset{\text{(Blue)}}{\text{Copper Sulphate}}+\text{Iron}\to \underset{\text{(Green)}}{\text{Iron Sulphate}}+\text{Copper}$

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