Question

Which reaction is an example of heterogeneous catalysis?

Ethene gas reacts with hydrogen gas by using a nickel catalyst.
Hydrogen peroxide decomposes by using an aqueous iodide ion catalyst.
Formic acid decomposes by using an acidic catalyst.
Sulfur dioxide gas is converted to sulfur trioxide gas by using nitrogen chloride gas.
@abb0t

Answer 1

The great majority of practical heterogeneous catalysts are solids and the great majority of reactants are gases or liquids (from wiki)

Answer 2

a heterogeneous catalyst takes the form of catalysis where the phase of the catalyst differs from that of the reactants.

Answer 3

So, A.