Give three tests for hydrochloric acid. Convert silver nitrate to a soluble salt of silver using hydrochloric acid and an alkali.

(i) When glass rod dipped in ammonia solution (NH₄OH) is brought near vapours of hydrochloric acid, dense white fumes of ammonium chloride are formed.

$\underset{\text{[aq.]}}{\text{NH}$3} + \underset{\text{[vapour]}}{\text{HCl}} \longrightarrow \underset{\text{[dense white fumes]}}{\text{NH}4\text{Cl}}

(ii) On addition of silver nitrate soln. to dil. HCl (acidified with dil. HNO₃), curdy white precipitate of silver chloride is obtained.

AgNO₃ + HCl ⟶ AgCl ↓ + HNO₃

(iii) On heating a mixture of manganese dioxide and conc. HCl, Greenish yellow gas (chlorine) is evolved.

MnO₂ + 4HCl ⟶ MnCl₂ ↓ + 2H₂O + Cl₂