Question

Name a substance that alters the speed of a chemical reaction but does not take part in the reaction.

Answer 1

A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change is known as a catalyst.

Example: $\underset{\mathrm{Chlorate}}{\underset{\mathrm{Potassium}}{2{\mathrm{KClO}}_3\left(\mathrm{s}\right)}}\stackrel{{\mathrm{MnO}}_2\left(\mathrm{s}\right)}{\to }\underset{\mathrm{Chloride}}{\underset{\mathrm{Potassium}}{2\mathrm{KCl}\left(\mathrm{s}\right)}}+\underset{\mathrm{Oxygen}}{3{\mathrm{O}}_2\left(\mathrm{g}\right)}$

Here magnesium oxide acts as a catalyst to increase the rate of a chemical reaction.