Match List-I with List-II:

Choose the correct answer from the options given below:

Let us match each industrial process with its correct application.

(a) Haber's process is used for the synthesis of ammonia ($$NH_3$$) from nitrogen and hydrogen: $$N_2 + 3H_2 \rightleftharpoons 2NH_3$$. This matches with (iii).

(b) Ostwald's process is used for the synthesis of nitric acid ($$HNO_3$$). In this process, ammonia is catalytically oxidised to nitric oxide, which is further oxidised and dissolved in water to produce $$HNO_3$$. This matches with (i).

(c) The Contact process is used for the synthesis of sulphuric acid ($$H_2SO_4$$). Sulphur dioxide is oxidised to sulphur trioxide using a $$V_2O_5$$ catalyst, and $$SO_3$$ is then absorbed in concentrated $$H_2SO_4$$ to form oleum, which is diluted to give $$H_2SO_4$$. This matches with (iv).

(d) The Hall-Heroult process is used for the extraction of aluminium by electrolysis of alumina ($$Al_2O_3$$) dissolved in molten cryolite ($$Na_3AlF_6$$). This matches with (ii).

The correct matching is (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii), which corresponds to Option (3).