When an iron nail is kept in a blue copper sulphate solution for some time, the solution turns light green and a reddish-brown coating forms on the nail. Which is the correct explanation for this observation?
Answer and explanation
Correct answer: Iron is more reactive than copper, so it displaces copper from copper sulphate.
Iron is above copper in the reactivity series. Therefore, iron displaces copper from copper sulphate solution:
\(
\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}
\)
The iron sulphate formed gives the solution a light-green colour, while displaced copper deposits as a reddish-brown coating on the nail. Option D is incorrect because dilution alone cannot produce a solid copper deposit.
Frequently asked questions
What is the correct answer to this question?
Iron is more reactive than copper, so it displaces copper from copper sulphate.
Why is this the correct answer?
Iron is above copper in the reactivity series. Therefore, iron displaces copper from copper sulphate solution:
\(
\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}
\)
The iron sulphate formed gives the solution a light-green colour, while displaced copper deposits as a reddish-brown coating on the nail. Option D is incorrect because dilution alone cannot produce a solid copper deposit.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
