Which of the following is an example of a homogeneous catalysis reaction?

1) $2 {\mathrm{SO}}_{2\left(\mathrm{g}\right)}+{\mathrm{O}}_{2\left(\mathrm{g}\right)}\stackrel{{\mathrm{NO}}_{\left(\mathrm{g}\right)}}{⟶}2 {\mathrm{SO}}_{3\left(\mathrm{g}\right)}$

2) Hydrolysis of aqueous sucrose solution in the presence of aqueous mineral acid

3) $2{\mathrm{SO}}_2\left(\mathrm{g}\right)\stackrel{\mathrm{Pt} \left(\mathrm{s}\right)}{\to }2{\mathrm{SO}}_3\left(\mathrm{g}\right)$

4) Hydrolysis of liquid ester in the presence of aqueous mineral acid

Homogenous catalysts are those in which the catalyst is in the same phase as the reactants and products.

In reaction-1, all reactants, products and catalyst are in gaseous state.

$2{SO}_{2\left(g\right)}+O_{2\left(g\right)}\stackrel{{NO}_{\left(g\right)}}{⟶}2{SO}_{3\left(g\right)}$ 

In reaction-2, all reactants, products and catalyst are in aqueous (liquid) state.

In reaction-4, all reactants, products and catalyst are in aqueous (liquid) state.

Hence, option D is the correct answer.