Write down the use of $ZSM-5$.

$A$ catalyst is a substance that . . . .

In the oxidation of oxalic acid by $KMnO_4$,the color of $KMnO_4$ disappears slowly at the start of the reaction but disappears very fast afterwards. This is an example of:

$2 SO_{2(g)} + O_{2(g)} \stackrel{V_{2}O_{5}}{\rightleftharpoons} 2 SO_{3(g)}$ is an example of

What is a catalyst?

The decomposition of $H_2O_2$ can be slowed down by the addition of a small amount of phosphoric acid,which acts as: