In the laboratory preparation of hydrogen from zinc & dilute hydrochloric acid - state a reason for

(a) Addition of traces of copper [II] sulphate to the reaction medium.

(b) Collecting the hydrogen by downward displacement of water and not air & collecting it after all the air in the apparatus is allowed to escape.

(c) Having the end of the thistle funnel dip below the level of the acid in the flask.

In the industrial method of preparation of hydrogen by the Bosch process - give

(a) Balanced equations for the first two main steps in the production of hydrogen

(b) The reason for use of addition of a promoter to the catalyst in the final step.

(c) The name of the solution which absorbs the unreacted carbon monoxide.

Draw labeled diagrams for two experiments to prove that - hydrogen is lighter than air.

Starting from hydrogen gas how would you obtain

(a) A neutral liquid

(b) A basic gas

(c) A metal by reduction of its heated oxide.

[the metal formed is above iron in the activity series]