Correct Answer - Option 2 : Combustion of coal
Concept:
In heterogeneous catalytic reactions, physical state of reactants and that of catalyst(s) used are different.
The hydrogenation of vegetable oils and Ostwald's process all are heterogeneous process. Combustion of coal is not heterogeneous catalytic reaction.
Haber's process:
\(N_2(g)+3H_2 \xrightarrow[]{FE(s),Mo(s)}2NH_3(g)\)
Catalyst is used.
Hydrogenation of vegetable oils:
\(vegetable oil(l)(Unsaturated) \xrightarrow[]{[(Ph_3P)]Cl orNi(s)}Vanaspathi(s)\)
Catalyst is used.
Ostwald's process:
\(4NH_3(g)+50_2 \xrightarrow[]{Pt(s), V_30_5(s)}4NO(g)+6H_2O(g)\)
Catalyst is used.
Combustion of coal:
C + O2 ⟶ CO2
(coal)
No catalyst is used in combustion of coal. The reaction is highly spontaneous in nature.