Question

Traces of molybdenum are used with finely divided iron which acts as a catalyst during Haber's process for the synthesis of ammonia. Here molybdenum:
A. acts as a promoter to increase the activity of the catalyst
B. acts as a poison to decrease the activity of the catalyst
C. provides a new pathway to the reaction
D. forms another intermediate compound with lesser activation energy

Answer 1

Hint: Any substance that increases the activity of a catalyst or which decreases the activation energy of the reactants such that the reaction can occur at a much faster rate are known as promoters. During the Haber’s process, Molybdenum is used as a promoter.

Complete step by step answer:
The substances which increase the rate of a chemical reaction and themselves remain quantitatively and chemically unchanged after the reaction are known as catalysts. Thus, catalysts are the substances that initiate the rate of a reaction.
Promoters are substances that enhance the activity of a catalyst while inhibitors poison a catalyst and decrease the activity of a catalyst.
In Haber’s process, the catalyst is used to initiate the rate of the reaction in order to get ammonia as the product at a much faster rate, finely divided iron is used. And to enhance the activity of iron, molybdenum is used as a promoter.
Thus, the correct option is A. acts as a promoter to increase the activity of the catalyst.

Note:
A catalyst is a substance that can be added to a reaction to increase the reaction rate without getting consumed in the process. Catalysts typically speed up a reaction by reducing the activation energy or changing the reaction mechanism. Enzymes are proteins that act as catalysts in biochemical reactions.