When an iron nail is placed in a blue copper sulphate solution, the solution gradually turns green and a reddish-brown coating forms on the nail. What type of reaction is this?
Answer and explanation
Correct answer: Displacement reaction
Iron is more reactive than copper, so it displaces copper from CuSO₄: Fe + CuSO₄ → FeSO₄ + Cu. FeSO₄ causes the green colour, while copper deposits on the nail. A combination reaction forms one product from reactants. Exam tip: use the reactivity series to identify displacement reactions.
Frequently asked questions
What is the correct answer to this question?
Displacement reaction
Why is this the correct answer?
Iron is more reactive than copper, so it displaces copper from CuSO₄: Fe + CuSO₄ → FeSO₄ + Cu. FeSO₄ causes the green colour, while copper deposits on the nail. A combination reaction forms one product from reactants. Exam tip: use the reactivity series to identify displacement reactions.
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.
