When an iron nail is placed in a blue copper sulphate solution, a reddish-brown copper coating forms on the nail and the solution turns pale green. What causes both changes?
Answer and explanation
Correct answer: Iron displaces copper from copper sulphate and forms iron sulphate.
Iron is more reactive than copper, so it displaces copper from copper sulphate solution. The reaction is \(\mathrm{Fe(s) + CuSO_4(aq) \rightarrow FeSO_4(aq) + Cu(s)}\). The released copper deposits as a reddish-brown coating on the nail, while the iron sulphate formed makes the solution pale green. Rusting in option B is a different process and does not produce a copper coating.
Frequently asked questions
What is the correct answer to this question?
Iron displaces copper from copper sulphate and forms iron sulphate.
Why is this the correct answer?
Iron is more reactive than copper, so it displaces copper from copper sulphate solution. The reaction is \(\mathrm{Fe(s) + CuSO_4(aq) \rightarrow FeSO_4(aq) + Cu(s)}\). The released copper deposits as a reddish-brown coating on the nail, while the iron sulphate formed makes the solution pale green. Rusting in option B is a different process and does not produce a copper coating.
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.
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