Question

A catalyst promoter ___________ the efficiency of a catalyst while a poison ________ the efficiency of the catalyst.

• A. decreases, increases
• B. decreases, decreases
• C. increases, increases
• D. increases, decreases

Answer 1

Answer: (D)

increases, decreases

A catalyst promoter increases the efficiency of a catalyst while a poison decreases the efficiency of the catalyst.

Substances which themselves are not catalysts but when mixed in small quantities with the catalysts increase their efficiency are called as promoters or activators. For example, in the Haber process for the synthesis of ammonia, traces of molybdenum increase the activity of finely divided iron which acts as a catalyst.

Substances that destroy the activity of the catalyst by their presence are known as catalytic poisons. For example, the platinum catalyst used in the oxidation of hydrogen is poisoned by $CO$.