Question

Vishakha takes a few wire pieces made up of different metals and places them in a blue solution of copper sulphate. What changes does she observe in the colour of the solutions present in beakers I, II, and III?

• A. I - Blue; II - Blue; III - Blue
• B. I - Green; II - Blue; III - Green
• C. I - Green; II - Blue; III - Blue
• D. I - Blue; II - Green; III - Green

Answer 1

The correct option is C I - Green; II - Blue; III - Blue

As iron is more reactive than copper, it displaces copper from copper sulphate solution. A green solution of iron sulphate is formed.
$Fe+CuS{O}_4\to FeS{O}_4+Cu$

Silver and gold are less reactive than copper. So, they do not displace copper from copper sulphate solution. Hence, the solution remains blue in colour.