Solved Example: 9189-01

The substance that increases the speed of a chemical reaction is called? (Army Soldier Tech (Pune) Nov 2020)

A. Inhibitor

B. Promoter

C. Catalyst

D. Moderator

Correct Answer: C

Solved Example: 9189-02

Substances that decrease the activity of a catalyst are known as: (RPSC Grade II Science Nov 2018)

A. Controllers

B. Promoters

C. Poisons

D. Initiators

Correct Answer: C

Solved Example: 9189-03

At the end of the chemical reaction the catalyst remains: (UP TGT Science 2019)

A. Unchanged in quantity but changed in composition

B. Unchanged in quantity and composition

C. Unchanged in composition but changed in quantity

D. Changed in quantity and composition

Correct Answer: B

Solved Example: 9189-04

Which of the following is not an example of heterogeneous catalytic reaction? (JEE Mains Paper I Jan 2019 Shift I)

A. Haber's process

B. Combustion of coal

C. Hydrogenation of vegetable oils

D. Ostwald's process

Correct Answer: B

Solved Example: 9189-05

Which of the following Catalyst is used during the Hydrogenation of Oils? (HP TGT Non-Medical TET 2021)

A. Pb

B. Ni

C. Pt

D. Cu

Correct Answer: B

A Catalyst is a substance which alters the rate of chemical reaction.

A Biocatalyst is a substance, especially enzymes or microbes, that initiates or modifies the rate of chemical reaction in a living body.

Advantages of Biocatalysts:

• Biocatalysts, like catalysts, increase the speed of chemical reactions but do not affect the thermodynamics of the reactions.
• Biocatalysts have high selectivity.
• High catalytic efficiency and mild operational conditions.
• Biocatalytic characteristics can be tailored with protein engineering and metabolic engineering methods to meet the desired process conditions.

Disadvantages of Biocatalysts:

• Limited operating regions, substrate or product inhibition, and reactions in only aqueous solutions.

Solved Example: 9191-01

Enzymes are biocatalysts and they catalyse biochemical reactions. Which of the following reactions is NOT catalysed by an enzyme?

A. Unwinding of two strands of DNA

B. Dissolution of CO$_2$ in water

C. Formation of peptide bond

D. Hydrolysis of sucrose

Correct Answer: B