What is the action of red litmus on (i) Dry ammonia gas (ii) Solution of ammonia gas is water?

Question

(a) What is the action of red litmus on

(i) Dry ammonia gas

(ii) Solution of ammonia gas is water?

(b) State the observations you would make on adding ammonium hydroxide to aqueous solution of

(i) furious sulphate

(ii) Aluminium chloride?

Answer 1

(a) (i) Red Litmus has no action on dry ammonia gas. Because it does not release any hydroxyl ions (OH^-) 

(ii) When it is passed through water ( NH₃ ) is converted to ammonia hydroxide (NH₄OH ). It dissociates to give hydroxyl ions (OH^- ) and the solution is basic in nature. Red litmus acquires a blue colour. 

(b) (i) A green precipitate of ferrous hydroxide will be formed by double decomposition reaction

FeSO₄ + 2NH₄OH ----------> Fe (OH)₂ (Green ppt.) + (NH₄)₂ SO₄

(ii) A white precipitate of aluminum hydroxide will be formed by double decomposition reaction

AlCl₃ + 3NH₄OH aq ---> Al(OH)₃ (White ppt.) + 3NH₄Cl