A, B, C and D summarize the properties of sulphuric acid depending on whether it is dilute or concentrated.

A: Typical acid property

B: Non-volatile acid

C: Oxidizing agent

D: Dehydrating agent

Choose the property [A, B, C or D] depending on which is relevant to each of the following:

(i) Preparation of hydrogen chloride gas.

(ii) Preparation of copper sulphate from copper oxide.

(iii) Action of conc. sulphuric acid on sulphur.

Give reasons why:

(i) Sodium Chloride will conduct electricity only in fused or aq. soln. state.

(ii) In the electroplating of an article with silver, the electrolyte sodium argentocyanide soln. is preferred over silver nitrate solution.

(iii) Although copper is a good conductor of electricity, it is a non-electrolyte.

(i) Name the solution used to react with Bauxite as a first step in obtaining pure aluminium oxide, in the Baeyer's process.

(ii) Write the equation for the reaction where the aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.

(iii) Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

(iv) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.

(v) Explain why it is preferable to use a number of graphite electrodes as anode instead of a single electrode, during the above electrolysis.

Identify the cations in each of the following case:

(i) NaOH solution when added to the solution 'A' gives a reddish brown precipitate.

(ii) NH₄OH solution when added to the solution 'B' gives a white ppt which does not dissolve in excess.

(iii) NaOH solution when added to the solution 'C' gives a white ppt which is insoluble in excess.