Question

In the laboratory preparation of ammonia, a student used $H_{2}S{O}_4$ for drying instead of CaO. Tell the repercussions of his action.

• A. $H_{2}S{O}_4$ and $N{H}_3$ reacts to give $O_2$ gas.
• B. $H_{2}S{O}_4$ and $N{H}_3$ reacts to form $(N{H}_4{)}_{2}S{O}_4$
• C. $N{H}_3$ and $H_{2}S{O}_4$ reacts to give $N_2$ gas.
• D. $N{H}_3$ and $H_{2}S{O}_4$ do not react with each other

Answer 1

The correct option is B $H_{2}S{O}_4$ and $N{H}_3$ reacts to form $(N{H}_4{)}_{2}S{O}_4$

In the laboratory, sulphuric acid cannot be used to prepare ammonia as sulphuric acid and ammonia react to form a salt. This is because of the basic nature of Ammonia due to which it reacts with the sulphuric acid to produce ammonium sulphate. The reaction of ammonia and sulphuric acid is given below:
$2N{H}_3+H_{2}S{O}_4\to (N{H}_4{)}_{2}S{O}_4$

Hence Quicklime ($CaO$) is used as a drying agent. Drying agents are substances capable of absorbing the moisture present in substances. Both of them being basic, quicklime can remove the moisture from ammonia without reacting with it. $CaO+N{H}_3\to$

No reaction but, quicklime reacts with water to form calcium hydroxide making it a suitable dehydrating agent. $CaO+H_{2}O\to Ca{\left(OH\right)}_2$