Question

The reaction rate refers to the change in concentration of a reactant or product per unit of time. if the pressure exerted on a gas increases, the reaction rate ____.

Answer 1

Answer: increases.

You can infere that from the fact that the pressure is proportional the the concentration, which in turn you can deduce from the ideal gas law:

pV = nRT

=> p = nRT / V = (n/V) RT

Where n/V is the concentration. So, you got that at constant T, p is proportional to the number concentration, which leads you to the conclusion that if the pressure exerted on a gas increases, the reaction rate increases.