Chemistry Reaction Kinetics MDCAT 2018
PMDC Verified Question 61 of 80
Role of a catalyst in a chemical reaction is to:
A
Increase rate of a reaction
B
Decrease yield of a reaction
C
Decrease rate of a reaction
D
Increase yield of product
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Increase rate of a reaction
Concept:

A positive catalyst alters the kinetics of a reaction without changing its thermodynamics.

Solution:

  • The core function of a catalyst is to increase the rate (speed) at which a chemical reaction approaches equilibrium.
  • It does this by lowering the activation energy barrier.
  • Importantly, a catalyst does NOT alter the equilibrium position, so it cannot increase or decrease the final yield of the product.


Why other options are incorrect:

Catalysts speed up equilibrium attainment but cannot shift thermodynamics to change the final yield. Decreasing the rate is the role of an inhibitor (negative catalyst).

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