Why can the solution turn green when an iron nail is placed in copper sulphate solution?
Answer and explanation
Correct answer: Due to the formation of iron(II) sulphate
Iron is more reactive than copper, so it displaces copper from copper sulphate solution: \(\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}\). The iron(II) sulphate formed gives the solution a pale green colour. Copper metal is also produced, but it deposits as a reddish-brown coating on the nail; it does not make the solution green.
Frequently asked questions
What is the correct answer to this question?
Due to the formation of iron(II) 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 iron(II) sulphate formed gives the solution a pale green colour. Copper metal is also produced, but it deposits as a reddish-brown coating on the nail; it does not make the solution green.
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.
