Question

Example of negative Catalysts.

Answer 1

Catalysts are the chemical substances that are used to increase the reaction without taking part in the reaction or getting consumed in the reaction. catalysts commonly increase the rate of reaction by reducing the activation energy or by changing the reaction mechanism. Catalysts are of two types positive catalyst and negative catalysts we will discuss both and see their examples.

Complete answer:
The type of catalyst that should be used is decided by the need or requirement of the reaction in which catalysts are supposed to be used. Catalyst are mainly of two types
Positive Catalyst: Catalysts which increase the rate of reaction are Positive catalysts. They increase the rate of reaction by decreasing the activation energy so the maximum number of reactant molecules can be converted into product molecules.
Example of Positive catalysts
Iron oxide in preparation of ammonia by Haber’s process behaves as a positive catalyst and increases the formation of ammonia.
Negative Catalyst: Catalysts which decrease the rate of reaction are negative catalysts. They decrease the rate of reaction by increasing the activation energy so the minimum number of reactant molecules can be converted to product molecules.
Example of negative catalysts
Phosphoric acid in decomposition of Hydrogen peroxide into water behaves as a negative catalyst and decreases the rate of reaction.
Alcohol in oxidation of Sodium sulphite behaves as a negative catalyst.
Alcohol also acts as a negative catalyst in oxidation of Chloroform.

Note:
There are some substances which affect the activity of a catalyst like Promoters. It is a substance that increases the activity of a catalyst. They are also known as accelerators. Inhibitors also known as Catalyst poison decreases the activity of a catalyst.