Catalysts

What substance poisons the iron catalyst in the Haber process?

• A) CO

• B) H₂S

• C) O₂

• D) NH₃

Catalyst poisoning occurs due to the presence of large amounts of impurities in the reactants.

• True

• False

A promoter is a substance that accelerates a chemical reaction on its own.

• True

• False

What is the term used to describe a catalyst that slows down a chemical reaction?

• A) Positive catalyst

• B) Promoter

• C) Inhibitor

• D) Enzyme

What happens when the temperature exceeds the enzyme’s optimum temperature?

• a) The reaction rate keeps increasing.

• b) The enzyme’s activity remains unaffected.

• c) The enzyme starts losing its activity, and the reaction stops

• d) The enzyme transforms into another catalyst.

Enzymes produce side products during reactions.

• True

• False

Type of catalysis

• A) homogeneous catalysis

• B) heterogeneous catalysis

• C) Both

The second step in the adsorption theory of heterogeneous catalysis is formation of activated complex

• True

• False

Semiconductors can be used as photocatalysts because their band gap energy is small enough to be bridged by light excitation.

• True

• False

What happens when a photocatalyst absorbs radiation?

• A) Chemical reactions stop

• B) Pairs of electrons and holes are generated

• C) The photocatalyst decomposes

• D) Only water is formed