It is prepared by dissolving ammonia in water.

An inverted funnel is used to prevent sucking back since ammonia is very soluble in water.

NH3 (g)+H2O(l)→NH4OH(g)

NITRIC ACID (HNO₃)

It is prepared in the laboratory by heating concentrated sulphuric acid (H₂SO₄) and sodium nitrate (NaNO₃).

H2SO4 (aq)+NaNO3 (aq)→NaHSO4 (aq)+HNO3 (aq)

Heating is done slowly to minimize the thermal decomposition of nitric acid.

All apparatus must be made of glass because HNO₃ attacks corks and rubber.

The nitric acid is yellow (brown) due to dissolved NO₂ formed by the thermal decomposition of HNO₃.

The brown color is removed by blowing air through the acid or it is allowed to stand for a few days.

Chemical Properties of Nitric Acid (HNO₃)

19. Concentrated Nitric Acid (HNO₃) oxidizes copper II ions.

Cu(s)+4HNO3 (aq)→Cu(NO)3 (aq)+2H2O(l)+2NO2 (g)

19. It reacts with alkalis to form salt and water.

HNO3 (aq)+NaOH(aq)→NaNO3 (aq)+H2O(l)

19. Concentrated Nitric Acid (HNO₃) reacts with iron (Fe) and aluminum (Al) to form a thin oxide layer which stops further reaction. This is why concentrated Nitric Acid (HNO₃) is exported in iron and aluminum containers.

Physical Properties of Nitric Acid (HNO₃)

19. It is very corrosive.
19. It normally contains 65% pure acid and 35% water.
19. It is a colorless fuming liquid; this is because, it contains dissolved nitrogen gas.

Uses of Nitric Acid

19. Used to make nitrogen fertilizers. Eg: NH₄NO₃, (NH₄)₃PO₄.
19. Used in making explosives such as gun powder.
19. Used in making plastics.

NB: Nitric Acid (HNO₃) can’t be use to generate hydrogen (H₂) directly because it is a strong oxidizing agent.