MCQ 71:
Which of the following is a factor that can affect the position of equilibrium in a reversible reaction?
A) Concentration of reactants
B) Pressure (for gaseous reactions)
C) Temperature
D) All of the above
Answer: D) All of the above
Explanation: The position of equilibrium can be influenced by changes in concentration, pressure, and temperature.
MCQ 72:
In a reaction, if increasing the temperature shifts the equilibrium position to the right, the reaction is:
A) Endothermic
B) Exothermic
C) At equilibrium
D) Spontaneous
Answer: A) Endothermic
Explanation: In an endothermic reaction, increasing the temperature shifts the equilibrium position to favor the formation of products.
MCQ 73:
Which of the following is a consequence of Le Chatelier’s principle?
A) Reactions can only occur at equilibrium.
B) The rate of a reaction will increase with increasing concentration of products.
C) Changes in conditions will shift the position of equilibrium.
D) Catalysts affect the position of equilibrium.
Answer: C) Changes in conditions will shift the position of equilibrium.
Explanation: Le Chatelier’s principle states that if an external change is applied to a system at equilibrium, the system will adjust to counteract that change.
MCQ 74:
For a chemical reaction at equilibrium, what happens if the concentration of a product is increased?
A) The equilibrium position shifts to the right.
B) The equilibrium position shifts to the left.
C) There is no effect on the equilibrium position.
D) The reaction will stop.
Answer: B) The equilibrium position shifts to the left.
Explanation: Increasing the concentration of a product will shift the equilibrium position to favor the reactants, reducing the amount of the product.
MCQ 75:
In a dynamic equilibrium, the rates of the forward and reverse reactions are:
A) Equal
B) Unequal
C) Zero
D) Increasing
Answer: A) Equal
Explanation: In dynamic equilibrium, the rate of the forward reaction equals the rate of the reverse reaction, resulting in constant concentrations of reactants and products.
MCQ 76:
The equilibrium constant (K) is a measure of:
A) The rate of reaction
B) The concentration of reactants at equilibrium
C) The ratio of the concentration of products to reactants at equilibrium
D) The activation energy of the reaction
Answer: C) The ratio of the concentration of products to reactants at equilibrium
Explanation: The equilibrium constant (K) expresses the relationship between the concentrations of products and reactants at equilibrium.
MCQ 77:
The Haber process, used for synthesizing ammonia, is an example of which type of reaction?
A) Decomposition
B) Synthesis
C) Combustion
D) Replacement
Answer: B) Synthesis
Explanation: The Haber process involves the synthesis of ammonia from nitrogen and hydrogen, making it a synthesis reaction.
MCQ 78:
Which of the following is NOT a factor that affects the equilibrium constant (K)?
A) Temperature
B) Concentration of reactants
C) Catalysts
D) Pressure
Answer: C) Catalysts
Explanation: Catalysts do not affect the equilibrium constant; they only speed up the rate at which equilibrium is reached without changing the position of equilibrium.
MCQ 79:
In an exothermic reaction, increasing the temperature will generally cause the equilibrium position to shift:
A) To the right
B) To the left
C) Not change
D) To the bottom
Answer: B) To the left
Explanation: In an exothermic reaction, increasing the temperature shifts the equilibrium position to favor the reactants.
MCQ 80:
Which of the following best describes a chemical equilibrium?
A) Reactants are completely converted to products.
B) The concentrations of reactants and products remain constant over time.
C) The reaction stops completely.
D) The forward reaction occurs much faster than the reverse reaction.
Answer: B) The concentrations of reactants and products remain constant over time.
Explanation: At equilibrium, the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products.
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