Consider the reaction below.

mg(s) + 2hcl(aq) --> h2(g) + mgcl2(aq)

what is the most likely effect of an increase in pressure on this reaction?

the reactant surface area increases.
the reaction rate decreases.
the reaction is not affected at all.
the reaction stops completely.

I believe the correct answer from the choices listed above is the second option. An increase in pressure on this reaction would be that the  reaction rate decreases and the reaction would tend to go the backward reaction. Hope this answers the question.

I am almost positive the answer is different temperatures.