Question
(a)
(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?
[3]
(b)
(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.
[3]
(c) For the preparation of hydrochloric acid in the laboratory:
(i) Why is direct absorption of hydrogen chloride gas in water not feasible?
(ii) What arrangement is done to dissolve hydrogen chloride gas in water?
[2]
(d) For the electro-refining of copper:
(i) What is the cathode made up of?
(ii) Write the reaction that takes place at the anode.
[2]