Question

51.If a zinc rod is dipped in copper sulphate solution, following changes will be noticed. Mark the correct observations.

(i) Zinc rod slowly loses its weight.

(ii) Copper settles at the bottom of the beaker.

(iii) Blue colour of copper sulphate disappears.

(A) (i) and (ii) only

(B) (i), (ii), and (iii)

(C) (i) and (iii) only

(D) (iii) only

Answer 1

When a zinc rod is dipped in copper sulfate solution, the following changes occur:

1. **Zinc rod slowly loses its weight**: This is correct because zinc displaces copper from copper sulfate, resulting in the loss of zinc's mass.
2. **Copper settles at the bottom of the beaker**: This is also correct as elemental copper is produced and can settle at the bottom.
3. **Blue color of copper sulfate disappears**: This is correct because as copper ions are displaced by zinc, the blue color associated with copper sulfate fades.

Based on this analysis, the correct answer is:

**(B) (i), (ii), and (iii)**.