A clean iron nail is placed in blue copper sulphate solution. A reddish-brown coating forms and the solution turns light green. Which conclusion is correct?
Answer and explanation
Correct answer: Iron displaces copper from its salt because iron is more reactive than copper.
The reactivity series shows that iron is more reactive than copper. Therefore iron displaces copper from copper sulphate according to Fe + CuSO₄ → FeSO₄ + Cu. Ferrous sulphate gives the solution a light green colour, and copper forms the reddish-brown coating. Hence B is correct. A reverses the reactivity relationship, while C and D ignore the formation of new substances.
Frequently asked questions
What is the correct answer to this question?
Iron displaces copper from its salt because iron is more reactive than copper.
Why is this the correct answer?
The reactivity series shows that iron is more reactive than copper. Therefore iron displaces copper from copper sulphate according to Fe + CuSO₄ → FeSO₄ + Cu. Ferrous sulphate gives the solution a light green colour, and copper forms the reddish-brown coating. Hence B is correct. A reverses the reactivity relationship, while C and D ignore the formation of new substances.
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.
