Question

when CuSO4 is added to a solution of ammonia

1) freezing point is lowerd

2) freeing point is raised

3) boiling point is raised

4) both 1 and 3

Answer 1

cuso4 is added to ammonia both 1 and 3 may be

Answer 2

Answer:

When $\mathrm{CuSO}_{4}$ is added to a solution of ammonia the “freezing point is raised”.

Explanation:

The reaction of $\mathrm{CuSO}_{4}$ with aqueous solution of ammonia can be written as:

$\bold{\mathrm{CuSO}_{4}(\mathrm{s})+4 \mathrm{NH}_{3}(\mathrm{aq}) \rightarrow\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{+2}(\mathrm{aq})+\mathrm{SO}_{4}^{-2}(\mathrm{aq})}$

Here we have 5 molecules at the reactant side and two ions at the product side. The depression in the freezing point and elevation in the boiling point are called as colligative properties as they depends on the number of ions present in the solution.

Hence due to the reaction of $\mathrm{CuSO}_{4}$ with ammonia, the number of ions decreases therefore the boiling point decreases and freezing point increases.