(i) Write the balanced chemical equation to prepare ammonia gas in the laboratory by using an alkali.
(ii) State why concentrated sulphuric acid is not used for drying ammonia gas.
(iii) Why is ammonia gas not collected over water?

Q. (i) How is ammonia gas prepared in laboratory starting from NH₄Cl? State the conditions and balanced equation for the preparation.
(ii) How is gas collected in a gas jar?
(iii) Name the substance used for drying ammonia gas. Why cannot substances such as conc. H₂SO₄, anhydrous calcium chloride and phosphorus pentoxide be used for drying ammonia gas?

Q.

(a) Name the chemicals required for the preparation of carbon dioxide in the laboratory.

(b) How will you collect the gas?

(c) Write the balanced chemical equation for the above reaction.

(d) Why is sulphuric acid not used for the preparation of carbon dioxide in the laboratory?

Q. (i) Name the acid used for the preparation of hydrogen chloride gas in the laboratory. Why is this particular acid preferred to other acids?
(ii) Write the balanced chemical equation for the laboratory preparation of hydrogen chloride gas.

Q. Assertion :The downward displacement of air method used for drying and collecting ammonia gas. Reason: Ammonia gas is lighter than air and hence collected by the downward displacement of air. Ammonia is not collected over water since it is highly soluble in water.(1 vol.of water dissolves about 702 vol.at 20C and 1 atm pressure). The drying agent used is calcium oxide.

Q. (a) Write a balanced chemical equation for the laboratory preparation of nitric acid.
(b) In the preparation of nitric acid from $KN{O}_3$, concentrated hydrochloric acid is not used in place of concentrated sulphuric acid. Explain why.
(c) Conc. nitric acid prepared in laboratory is yellow in colour. Why? How is this colour removed? [4 MARKS]