Revise smart, understand Better

5/27 MCQs for:

MATTER: PROPERTIES AND TRANSFORMATION: Reversible Reactions

The breaking up or splitting of a compound by heat into simpler substances which do not recombine on cooling to give the original substance is known as:

Thermal decomposition.

Thermal dissociation.

Decomposition.

Dissociation.

A reversible reaction is said to have attained equilibrium when:

The rate of the forward reaction is equal to the rate of the backward reaction and the concentrations of reactants and products remain constant.

The rate of the forward reaction is equal to the rate of the backward reaction and the concentrations of reactants and products are the same.

The rate of the forward reaction is equal to the rate of the backward reaction.

The rate of the forward reaction is not equal to the rate of the backward reaction and the concentrations of reactants and products remain constant.

Consider the equilibrium reaction below occurring in a closed system:
CaCO_{3 (s)} ⇌ CaO_(s) + CO_{2 (g)}.
According to Le Chatelier’s principle:

If more carbon dioxide is added to the system, the position of equilibrium will shift to the left to use up the extra amount added.

All are correct.

If the amount of calcium oxide is reduced, the equilibrium position will shift to the right to produce more calcium oxide that replaces the quantity removed.

If amount of calcium carbonate is increased, the equilibrium position will shift to the right to consume the extra amount added, and if reduced, the equilibrium position will shift to the left to replace the amount removed.

For chemical equilibrium to be established:

The reaction must be reversible.

The reaction must be taking place in a closed system (especially for reactions involving gases).

The reaction must be taking place in an open system (especially for reactions involving gases).

The reaction must be reversible and the reaction must be taking place in a closed system (especially for reactions involving gases).

Consider the following reaction system in equilibrium:
2SO_{2 (g)} + O_{2 (g)} ⇌ 2SO_{3 (g)} ∆H=-197KJmol⁻¹
According to Le Chatelier’s principle, if the temperature is increased.

The equilibrium position will shift to the left i.e. the exothermic reaction will be favoured so as to replenish the heat removed from the system.

The equilibrium position will shift to the right i.e. the exothermic reaction will be favoured so as to replenish the heat removed from the system.

The equilibrium position will shift to the left favouring the endothermic reaction so that the extra heat added is used up.

The equilibrium position will shift to the right and then to the left i.e. the exothermic reaction will be favoured so as to replenish the heat removed from the system.