Catalyst and Catalysis MCQs

A catalyst is a substance that accelerates the rate of a reaction, a process known as catalysis. The term ‘catalyst’ was introduced by Berzelius in 1835. Catalysts influence both the forward and reverse reactions equally, so they do not change the equilibrium constant. They participate in the reaction but remain unchanged after the reaction is complete. Conversely, a substance that slows down the rate of a reaction is called an inhibitor. A catalyst operates by creating a temporary intermediate complex, which eventually breaks down to produce the final product, allowing the catalyst to be restored to its original state.

Which of the following enzymes catalyses the hydrolysis of triglycerides to fatty acids and glycerol?

(a) Pepsin
(b) Maltase
(c) Zymase
(d) Lipase

Which of the following is incorrect for a catalyst?

(a) Bio-chemical reactions are mostly catalysed by enzymes
(b) Catalyst does not start a reaction
(c) Catalyst changes the equilibrium constant of a reaction
(d) Co-enzymes increase the activity of an enzyme

Which of the following is incorrect for enzymes?

(a) Enzymes are specific
(b) Most of the enzymes are protein
(c) Reactivity of enzymes is least at optimum temperature
(d) High temperature and UV rays can denature enzymes

Ziegler Natta catalyst is associated with

(a) polymerisation of alkenes
(b) hydrogenation of alkenes
(c) hydroformylation of alkenes
(d) none of the above

How does a catalyst increase the rate of a reaction?

(a) By forming an intermediate complex
(b) By increasing activation energy
(c) By lowering the activation energy
(d) By changing equilibrium constant

Which of the following is used as a catalyst in the lead chamber process?

(a) Nitrogen oxides
(b) Pt
(c) Ni
(d) V₂O₅

Which of the following is known as Lindlar’s catalyst?

(a) Na in liquid NH₃
(b) Pt in ethanol
(c) Pd with BaSO₄
(d) Ni in ethanol

What is the effect of enzymes on the rate of biochemical reactions?

(a) The rate increases
(b) It does not change
(c) The rate decreases
(d) either (b) or (c)

Which of the following is changed in a chemical reaction due to a catalyst?

(a) Internal energy
(b) Entropy
(c) Enthalpy
(d) Activation energy

Which of the following is used as a catalyst in the contact process?

(a) V₂O₅
(b) Fe₂O₃
(c) Ag₂O
(d) SO₃