Give the laboratory preparation of:

(a) Ammonia

(b) Nitric acid

(a)

1. Ammonium chloride (NH₄Cl) and calcium hydroxide (Ca(OH)₂) are mixed together. (Excess of calcium hydroxide is mixed well with ammonium chloride).

2. Reactants are finely grounded and taken in a round-bottom flask fitted in a slanting position, mouth downwards.

3. On heating the mixture, ammonia gas is evolved.
   2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

4. Ammonia gas is collected in inverted gas jars by the downward displacement of air because it is lighter than air and highly soluble in water and therefore, it cannot be collected over water.

5. Quicklime (CaO) is used as a drying agent.

(b)

1. Nitric acid is obtained by distilling conc. sulphuric acid with potassium nitrate KNO₃ (nitre) or sodium nitrate NaNO₃ (Chile saltpetre).
2. A mixture of equal parts, by weight, of potassium/sodium nitrate and concentrated sulphuric acid is heated gently to 180°C-200°C in a glass retort.
3. Sulphuric acid is a non-volatile acid and produces volatile nitric acid on reacting with potassium nitrate or sodium nitrate.

$\underset{[conc.]}{\text{KNO}$3} + \underset{[conc.]}{\text{H}2\text{SO}4} \xrightarrow{\lt 200 \degree\text{C}} \underset{[acid \space salt]}{\text{KHSO}4} + \text{HNO}_3

$\underset{[conc.]}{\text{NaNO}$3} + \underset{[conc.]}{\text{H}2\text{SO}4} \xrightarrow{\gt 200 \degree\text{C}} \underset{[acid \space salt]}{\text{NaHSO}4} + \text{HNO}_3

4. The vapours of nitric acid are condensed to a light yellow liquid by chilling the receiver with running cold water.