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ICSE Class 9 Chemistry Question 13 of 18

Chemical Changes and Reactions — Question 10

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Question

Question 1(x)

Aman performed the following four experiments

Aman performed the following four experiments. Concise Chemistry Solutions ICSE Class 9.

The experiments in which the blue colour of the solution will fade are :

  1. P and Q

  2. P, Q and R

  3. Q and R

  4. Q, R and S

Answer

Q and R

Reason — Blue colour is because of CuSO4. In experiment Q, zinc displaces copper from copper sulphate solution because zinc is more reactive and present above copper in reactivity series.

CuSO4 (aq) + Zn ⟶ ZnSO4 + Cu ↓

In experiment R, iron displaces copper from copper sulphate solution because iron is also more reactive and present above copper in reactivity series.

Fe iron+CuSO4 blue sol. (aq.)⟶FeSO4 green sol.+Cu copper-brown red deposit\underset{\text{ iron}}{\text{Fe}} + \underset{\text{ blue sol.}}{\text{CuSO}_4}\text{ (aq.)} \longrightarrow \underset{\text{ green sol.}}{\text{FeSO}_4} + \underset{\text{ copper-brown red deposit}}{\text{Cu}}

Hence, in experiment Q and R, copper is displaced by more reactive metal. So, the blue colour of the solution will fade.