Question

What is the role of promoters and poisons in catalysis?

Answer 1

Catalysis is the process which increases the rate of a chemical reaction i.e. the reaction which takes 10-12 hours can be done within an hour by adding a substance in it that substance is called catalyst and the process called catalysis. Catalysts are not consumed in the catalyzed reaction but can act repeatedly. Often only very small amounts of catalyst are required to increase the rate of reaction.

Complete Step by step solution: Substances which are not catalyst by themselves but when they get mixed even in small quantities with a reaction mixture they increase the efficiency of that mixture. Promoters can also be known by other names called activators. The main example of a promoter is addition of some traces of molybdenum in the Haber’s process which is generally the process of synthesis of ammonia in this reaction Mo acts as a promoter which increases the activity of reaction and acts as a catalyst.
-While poisons are those substances which when get mixed with the reaction mixture it decreases the activity of the catalyst. The example of poison is shown in the synthesis of Haber’s process in which the activity of iron catalyst is destroyed in the presence of or CO which acts as a poison.

Note: By increasing the temperature there is an increase in the catalytic power of a catalyst but after a certain temperature its power begins to decrease. A catalyst has thus a particular temperature at which its catalytic activity is maximum. This temperature is termed as optimum temperature.