Question

How would adding the catalyst nitrogen monoxide (NO) affect this reaction?

Answer 1

Answer: A) NO increases the rate at which $SO_3$ molecules are formed.

Explanation:

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more reactant molecules can cross the energy barrier by undergoing collisions and convert to products.

$2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)$

Thus NO will increase the rate of reaction by lowering the activation energy and thus the colllisions among $SO_2$ and $O_2$ molecules will incraese which in turn will lead to formatioon of more $SO_3$ molecules.