Question

What is a heterogeneous reaction?

Answer 1

It's a reaction involving different phases.

Explanation:

This is an example of a homogenous reaction:

`A(g) + B(g) -> C(g) + D(g)`

In this case, all of our reactants and products are gases.
But, if any of these reactants or products are in a different phase than gases, that would make the reaction heterogenous:

`A(s) + B(g) -> C(g) + D(g)`

The reaction above would be considered a heterogenous reaction.

It is also important to note that heterogenous reactions are not only reactions where reactants and products are in different phases.

They can also be reactions which take place on the surface of a catalyst in a different phase.