Question

In presence of acetanilide, the rate of decomposition of ${H_2}{O_2}$ is reduced. Acetanilide is called a positive catalyst.
A) True.
B) False.

Answer 1

We know that the catalysts are the substances which alter the speed of reaction by changing the track of reaction. Most of the time a catalyst is employed to hurry up or increase the speed of the reaction.

Complete step by step answer:
We know that there are few reactions during which a catalyst can hamper the reaction. These sorts of catalysts are called as negative catalysts.
The energy of activation of the catalyzed reaction within the presence of acetanilide is $112{\text{ }}KJ/mol$ which is greater than that of an uncatalyzed reaction. This implies that the speed of decomposition of ${H_2}{O_2}$ is decreased within the presence of acetanilide and hence it's a negative catalyst.
Therefore, it is a false statement.

Note:
Now we can discuss about how catalyst, promoter and catalyst poison differ from each other as,
Types of catalyst:

Catalysts which increase the speed of a reaction are positive catalysts. It increases the speed of reaction by lowering the energy of activation barriers such that an outsized number of reaction molecules are converted into products, thereby the share of yield of products increase.

Example:
The energy of activation of a catalyzed reaction in presence of $Mn{O_2}$ catalyst is $49{\text{ }}KJ/mol$ but the energy of activation of an uncatalyzed reaction is $86{\text{ }}KJ/mol$ which means that the speed of decomposition of ${H_2}{O_2}$ is increased within the presence of $Mn{O_2}$ and hence it's a positive catalyst.

Promoter:
A substance which increases the catalyst activity are referred to as Promoters.
Catalyst Poisons:
Substances which decrease the catalyst activity are referred to as catalyst poisons.