A student placed a clean iron nail in blue coloured copper sulphate solution for a considerable time. He observes that :
  1. iron nail gets green coating
  2. iron nail gets brown coating
  3. iron nail gets no coating
  4. iron nail gets blue coating

Correct answer: (2) iron nail gets brown coating

Explanation: When an iron nail is placed in a copper sulphate solution, it displaces copper from its solution as iron is more reactive than copper. Hence, a brown layer of copper metal is observed on the iron strip.

The chemical equation for the reaction is given below:

$Fe (s) (grey) + CuSO_4 (aq) (blue) → FeSO_4 (aq) (green) + Cu(s) (brown)$


Simply Easy Learning

Updated on: 10-Oct-2022


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