(i) Oxidation of sulphur dioxide to form sulphur trioxide. In this reaction, Pt acts as a catalyst.

2SO_2(g) \(\overset{Pt(s)}\longrightarrow\) 2SO_3(g)

(ii) Formation of ammonia by the combination of dinitrogen and dihydrogen in the presence of finely divided iron.

N_2(g) + 3H_2(g) \(\overset{Fe(s)}\longrightarrow\) 2NH_3(s)

This process is called the Haber's process.

(iii) Oswald's process: Oxidation of ammonia to nitric oxide in the presence of platinum.

4NH_3(g) + 5O_2(g) \(\overset{Pt(s)}\longrightarrow\) 4NO(g) + 6H₂O_(g)

(iv) Hydrogenation of vegetable oils in the presence of Ni.

Vegetable oil(l) + H_2(g) \(\overset{Ni(s)}\longrightarrow\) vegetable ghee