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.

Answer 1

Hetero means different. In this instance it's talking about different phases.
A is the correct answer becuase you're using a solid nickel catalyst with gasses.
The rest are in the liqud phase.

Answer 2

it follows anti-markovnikov rules with peroxides.