Chemical Equilibrium Practice Questions
HSC/SSC (Bangladesh) · HSC Chemistry · 149 free MCQs with instant results and detailed explanations.
149
Total
48
Easy
75
Medium
26
Hard
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Sample Questions from Chemical Equilibrium
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
In a chemical equilibrium, the rate of the forward reaction is:
A.
equal to the rate of the reverse reaction
B.
greater than the rate of the reverse reaction
C.
less than the rate of the reverse reaction
D.
independent of the reverse reaction
Show Answer & Explanation
Correct Answer: A
At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction, resulting in no net change in the concentration of reactants and products.
Q2
Easy
If the concentration of a reactant in a reversible reaction is decreased, the equilibrium will shift:
A.
to the left
B.
to the right
C.
not at all
D.
depends on temperature
Show Answer & Explanation
Correct Answer: B
According to Le Chatelier's principle, if a reactant's concentration is decreased, the equilibrium will shift to the right to produce more products.
Q3
Easy
In an exothermic reaction at equilibrium, increasing the temperature will:
A.
favor the forward reaction
B.
favor the reverse reaction
C.
not affect the equilibrium
D.
shift equilibrium to the right
Show Answer & Explanation
Correct Answer: B
For an exothermic reaction, increasing temperature shifts the equilibrium to the left (reverse reaction) to absorb the added heat, thereby favoring the formation of reactants.
Q4
Medium
What happens to the position of equilibrium in the synthesis of ammonia (N2 + 3H2 ⇌ 2NH3) when temperature is increased?
A.
It shifts to the right.
B.
It shifts to the left.
C.
No change occurs.
D.
It shifts to a gaseous state.
Show Answer & Explanation
Correct Answer: B
Increasing the temperature shifts the equilibrium position of an exothermic reaction to the left, favoring the reactants. The synthesis of ammonia is exothermic, hence the shift occurs.
Q5
Medium
In the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g), if the volume of the container is decreased, what will be the effect on the equilibrium position?
A.
It shifts to the right.
B.
It shifts to the left.
C.
It remains unchanged.
D.
It produces more O2.
Show Answer & Explanation
Correct Answer: A
Decreasing the volume increases pressure, and according to Le Chatelier's principle, the equilibrium will shift towards the side with fewer gas molecules. The right side has 2 moles of gas compared to 3 on the left.
Q6
Medium
At equilibrium, the concentration of N2 is 0.3 M, H2 is 0.9 M, and NH3 is 0.2 M in the reaction N2(g) + 3H2(g) ⇌ 2NH3(g). What is the equilibrium constant Kc for this reaction?
A.
1.5
B.
0.75
C.
0.25
D.
2.0
Show Answer & Explanation
Correct Answer: A
The equilibrium constant Kc is calculated using the formula Kc = [NH3]^2 / ([N2][H2]^3). Plugging in the values gives Kc = (0.2^2) / (0.3 * (0.9^3)) = 1.5.
Q7
Medium
Which of the following statements about chemical equilibrium is incorrect?
A.
At equilibrium, the rate of forward reaction equals the rate of reverse reaction.
B.
Equilibrium can be achieved only in a closed system.
C.
Concentrations of reactants and products remain constant.
D.
Equilibrium is reached only when all reactants are converted to products.
Show Answer & Explanation
Correct Answer: D
Equilibrium is reached when the rates of the forward and reverse reactions are equal, not necessarily when all reactants are converted to products. Some reactants remain at equilibrium.
Q8
Hard
In a reversible reaction at equilibrium, if the concentration of the reactants is increased, what will happen to the position of equilibrium according to Le Chatelier's principle?
A.
Shift to the right, favoring products
B.
Shift to the left, favoring reactants
C.
Remain unchanged
D.
Increase the rate of reaction without shifting
Show Answer & Explanation
Correct Answer: A
According to Le Chatelier's principle, if the concentration of reactants is increased, the system will respond by shifting the equilibrium position to the right, favoring the formation of products to reduce the effect of the change.
Q9
Hard
At a certain temperature, the equilibrium constant Kc for the reaction N2(g) + 3H2(g) ⇌ 2NH3(g) is 6.0. If the initial concentrations of N2 and H2 are both 1.0 M, what is the equilibrium concentration of NH3?
A.
0.5 M
B.
1.0 M
C.
1.5 M
D.
2.0 M
Show Answer & Explanation
Correct Answer: B
At equilibrium, if we set the change in concentration of NH3 as +2x, the change in N2 as -x, and in H2 as -3x, we can derive the equilibrium concentrations and substitute them into the Kc expression to find that the equilibrium concentration of NH3 is 1.0 M.
Q10
Hard
For the equilibrium reaction N2(g) + 3H2(g) ⇌ 2NH3(g), if the concentration of NH3 is increased, what will happen to the equilibrium according to Le Chatelier's principle?
A.
The equilibrium will shift to the left.
B.
The equilibrium will shift to the right.
C.
The equilibrium will remain unchanged.
D.
The reaction rate will increase.
Show Answer & Explanation
Correct Answer: A
According to Le Chatelier's principle, if the concentration of a product (NH3) is increased, the equilibrium will shift to the left (towards the reactants) to counteract the change and reduce the concentration of NH3.
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Chemical Equilibrium — HSC/SSC (Bangladesh) HSC Chemistry Practice Questions Online
This page contains 149 practice MCQs for the chapter Chemical Equilibrium in HSC/SSC (Bangladesh) HSC Chemistry. The questions are organized by difficulty — 48 easy, 75 medium, 26 hard — so you can choose the right level for your preparation.
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