Le Chatelier Principle and its Application MCQs

Le Chatelier Principle and its Application MCQs

When a reaction reaches equilibrium, the forward and reverse reactions occur at the same rate, and the concentrations of the reactants and products remain constant as long as the system is undisturbed. But what happens when this equilibrium is disrupted? In 1888, Henry Le Chatelier introduced what is now known as the Le Chatelier principle. This principle states that if an external stress is applied to a system at equilibrium, the system will adjust to partially counteract that stress. Essentially, when a stress is applied to a chemical equilibrium, the equilibrium position shifts in the direction that reduces the applied stress.

In which of the following cases does the reaction go farthest to completion?

(a) K = 1
(b) K = 10
(c) K = 10^-2
(d) K = 10²

When a catalyst is added to a reversible reaction in equilibrium state the value of the equilibrium constant

(a) increases
(b) decreases
(c) does not change
(d) becomes zero

The role of a catalyst in a reversible reaction is to

(a) alter the equilibrium constant of the reaction
(b) increase the rate of the forward reaction
(c) allow the equilibrium to be achieved quickly
(d) decrease the rate of backward reaction

A vessel at equilibrium contains SO3, SO2 and O2, now some helium gas is added so that total pressure increases while temperature and volume remain constant. According to Le Chatelier Principle the dissociation of SO32-

(a) decreases
(b) remain constant
(c) increases
(d) change unpredictably

The equilibrium constant of a reaction is 300. If the volume of reaction flask is tripled the equilibrium constant is

(a) 300
(b) 600
(c) 900
(d) 100

The chemical equilibrium of a reversible reaction is not influenced by

(a) temperature
(b) pressure
(c) catalyst
(d) concentration

For a reversible reaction the concentration of the reactants are doubled, then the equilibrium constant

(a) becomes one-fourth
(b) is doubled
(c) is halved
(d) remains the same

In what manner will increase of pressure affect the following equation

C(s) + H2O → CO(g) + H2(g)

(a) shift in the reverse direction
(b) shift in the forward direction
(c) increase in the yield of hydrogen
(d) no effect

Le Chatelier Principle is applicable to

(a) heterogeneous reaction
(b) homogeneous reaction
(c) irreversible reaction
(d) system in equilibrium

The equilibrium between water and its vapour in an open vessel

(a) can be achieved
(b) depends upon pressure
(c) cannot be achieved
(d) depends upon temperature