Q. How does dilution affect a reaction at equilibrium involving aqueous solutions?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the rate of reaction
Solution
Dilution decreases the concentration of reactants and products, and according to Le Chatelier's Principle, the equilibrium will shift to the left to produce more reactants.
Correct Answer:
B
— Shifts equilibrium to the left
Q. How does increasing temperature affect an exothermic reaction at equilibrium?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the rate of reaction
Solution
For an exothermic reaction, increasing the temperature shifts the equilibrium to the left, favoring the reactants, as the system tries to absorb the added heat.
Correct Answer:
B
— Shifts equilibrium to the left
Q. How does the addition of an inert gas at constant volume affect the equilibrium of a reaction?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the reaction rate
Solution
Adding an inert gas at constant volume does not change the partial pressures of the reactants or products, thus having no effect on the equilibrium position.
Q. In a chemical equilibrium, what does a large equilibrium constant (K) indicate?
A.
Products are favored at equilibrium
B.
Reactants are favored at equilibrium
C.
Equilibrium is not established
D.
Reaction is slow
Solution
A large equilibrium constant (K) indicates that at equilibrium, the concentration of products is much greater than that of reactants, favoring products.
Correct Answer:
A
— Products are favored at equilibrium
Q. In a reaction where heat is a product, what happens if the temperature is decreased?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the rate of reaction
Solution
Decreasing the temperature in an exothermic reaction (where heat is a product) shifts the equilibrium to the right, favoring the formation of products.
Correct Answer:
A
— Shifts equilibrium to the right
Q. What happens to the equilibrium position of a reaction when the concentration of a reactant is increased?
A.
The equilibrium shifts to the right
B.
The equilibrium shifts to the left
C.
The equilibrium remains unchanged
D.
The reaction stops
Solution
According to Le Chatelier's Principle, increasing the concentration of a reactant will shift the equilibrium position to the right to favor the formation of products.
Correct Answer:
A
— The equilibrium shifts to the right
Q. What happens to the equilibrium position when the concentration of a reactant is increased in a reversible reaction?
A.
The equilibrium shifts to the right
B.
The equilibrium shifts to the left
C.
The equilibrium remains unchanged
D.
The reaction stops
Solution
According to Le Chatelier's Principle, increasing the concentration of a reactant will shift the equilibrium position to the right to favor the formation of products.
Correct Answer:
A
— The equilibrium shifts to the right
