Why does a reddish-brown coating form on an iron nail and the solution turn green when the nail is placed in copper sulphate solution?
Answer and explanation
Correct answer: Iron displaces copper and forms iron sulphate.
Iron is more reactive than copper, so it displaces copper from copper sulphate solution: \(\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}\). The displaced copper deposits as a reddish-brown coating on the nail, while the iron sulphate formed makes the solution green. Unlike option A, copper cannot displace iron because copper is less reactive.
Frequently asked questions
What is the correct answer to this question?
Iron displaces copper and forms iron sulphate.
Why is this the correct answer?
Iron is more reactive than copper, so it displaces copper from copper sulphate solution: \(\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}\). The displaced copper deposits as a reddish-brown coating on the nail, while the iron sulphate formed makes the solution green. Unlike option A, copper cannot displace iron because copper is less reactive.
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.
