A student places a clean zinc strip in a blue copper sulphate solution. After some time, a reddish-brown coating forms on the strip and the blue colour of the solution fades. Which is the correct explanation of this observation?
Answer and explanation
Correct answer: Zinc is more reactive than copper, so it displaces copper from copper sulphate.
Zinc is more reactive than copper. Therefore, zinc displaces copper from copper sulphate solution:
\(\mathrm{Zn + CuSO_4 \rightarrow ZnSO_4 + Cu}\)
The reddish-brown coating is deposited copper, and the blue colour fades because blue \(\mathrm{Cu^{2+}}\) ions are removed from the solution. Unlike option B, copper cannot displace zinc because copper is less reactive than zinc.
Frequently asked questions
What is the correct answer to this question?
Zinc is more reactive than copper, so it displaces copper from copper sulphate.
Why is this the correct answer?
Zinc is more reactive than copper. Therefore, zinc displaces copper from copper sulphate solution:
\(\mathrm{Zn + CuSO_4 \rightarrow ZnSO_4 + Cu}\)
The reddish-brown coating is deposited copper, and the blue colour fades because blue \(\mathrm{Cu^{2+}}\) ions are removed from the solution. Unlike option B, copper cannot displace zinc because copper is less reactive than zinc.
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.
