Chemistry Equilibrium SET 2019
PMDC Verified Question 75 of 102
Which one of the following factors does not affect the equilibrium position?
A
Catalyst
B
Concentration of reactants and product
C
Temperature
D
Pressure
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Catalyst
Concept:

The equilibrium position is determined by the ratio of products to reactants. Only factors that selectively favor forward or backward reactions can shift this position.

Formula:

$$ K_c = \frac{[\text{Products}]}{[\text{Reactants}]} $$

Solution:

  • A catalyst functions by lowering the activation energy for both the forward and reverse reactions equally.


  • Because both rates increase by the same factor, the system reaches equilibrium faster, but the final ratio of products to reactants (the equilibrium position) remains completely unchanged.


Why other options are incorrect:

Concentration, temperature, and pressure all actively disturb equilibrium as dictated by Le Chatelier's Principle.

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