Chemistry Problems on “Factors Affecting Equilibria”.
1. Which of the following factors do you think will not affect the state of the equilibrium?
a) concentration
b) pressure
c) temperature
d) color
Answer: d
Clarification: According to Le chatelier’s principle, if a system at equilibrium is subjected to a change in concentration, pressure or temperature the equilibrium shifts in the direction that tends to nullify the effect of the change.
2. What will happen if at equilibrium the concentration of one of the reactants is increased?
a) equilibrium will shift in the forward direction
b) equilibrium population will not change
c) equilibrium will shift in the backward direction
d) equilibrium will move to and fro
Answer: a
Clarification: As per the Le chatelier’s principle, if the concentration of one of the reactants is increased at equilibrium the equilibrium will shift in the forward direction and vice versa is also possible. Therefore we can say that there is an effect of change of concentration on equilibrium.
3. In the reaction, H2(g) + Br2(g) (rightleftharpoons) 2HBr(g), what will happen if there is a change in pressure?
a) equilibrium moves left
b) equilibrium moves right
c) there is no change in equilibrium
d) we cannot say
Answer: c
Clarification: According to Le chatelier’s principle, there will be no effect of pressure on equilibrium if the chemical equation has the same number of moles of reactants and products hear the moles on the left side is equal to the moles on the right side that is 2.
4. Consider the chemical equation TiCl4 + 2 H2O (rightleftharpoons) TiO2 + 4 HCl if the pressure is increased what will happen to the equilibrium?
a) it moves backward direction
b) moves forward direction
c) remains constant
d) cannot say
Answer: a
Clarification: When there is a change in a number of moles, the equilibrium will shift in the direction having a smaller number of moles when the pressure is increased and vice-versa. Here the equilibrium moves in the backward direction because the reactants have less number of moles than products.
5. If a reaction produces heat during the process then it is ____________
a) exothermic
b) endothermic
c) both exothermic and endothermic
d) neither exothermic nor endothermic
Answer: a
Clarification: If a reaction releases heat then it is exothermic in nature and if the reaction consumes heat it is endothermic in nature. An example of the exothermic reaction is the mixing of washing soda in water and mixing glucose in water is an example of an endothermic reaction.
6. The formation of products is favoured by ____________ temperature in an endothermic reaction.
a) high
b) low
c) moderate
d) 0
Answer: a
Clarification: When the process is exothermic, low temperature of favors Forward reaction and when the process is endothermic high temperature favors the formation of the products. This is according to le chatelier’s principle.
7. At constant pressure, if the inert gases added then the equilibrium will shift in the direction of ___________
a) decrease in the number of moles
b) increase in the number of moles
c) does not depend on the number of moles
d) does not change
Answer: b
Clarification: At constant pressure, if inert gas added, it will increase the volume of the system there for the equilibrium will shift in a direction, in which there is an increase in the number of moles of gases as per le chatelier’s principle.
8. Which side does the catalyst shift the equilibrium position?
a) left side
b) right side
c) may be left or right side
d) does change the position
Answer: d
Clarification: As per Le chatelier’s principle on the effect of catalyst states that the presence of the catalyst does not change the position of the equilibrium it simply fast and the attainment of the equilibrium.
9. The equilibrium position does not change when there is an addition of inert gas at constant volume.
a) true
b) false
Answer: a
Clarification: If keeping the volume of the system constant and inert gases added the relative molar concentration of the substance will not change hence the equilibrium position of the reaction remains unaffected.
10. What will happen to the position of equilibrium if the concentration of one of the products is increased?
a) shifts left
b) shift right
c) does not change
d) main shift left or right
Answer: a
Clarification: According to Le chatelier’s principle if at equilibrium the concentration of one of the products is increased the equilibrium will shift in the backward direction that is towards the left side and vice versa.
Chemistry Problems,