Equilibrium Practice Questions
Class 11 · Chemistry · 1739 free MCQs with instant results and detailed explanations.
1739
Total
606
Easy
855
Medium
278
Hard
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Topics in Equilibrium
Le Chatelier's Principle
347
Chemical Equilibrium
327
Ionic Equilibrium
321
pH Scale
312
Buffer Solutions
432
Sample Questions from Equilibrium
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
If the concentration of a reactant in a reversible reaction decreases, what will happen to the rate of the forward reaction?
A.
Increase
B.
Decrease
C.
Remain constant
D.
Stop completely
Show Answer & Explanation
Correct Answer: B
According to Le Chatelier's principle, decreasing reactant concentration slows down the forward reaction rate.
Q2
Easy
Which of the following is true regarding equilibrium?
A.
The concentrations of reactants and products are equal.
B.
The rates of forward and reverse reactions are equal.
C.
All reactions reach equilibrium.
D.
Temperature change does not affect equilibrium.
Show Answer & Explanation
Correct Answer: B
At equilibrium, the rates of the forward and reverse reactions are equal, not necessarily their concentrations.
Q3
Easy
Which factor does NOT affect the position of equilibrium in a reversible reaction?
A.
Temperature
B.
Pressure
C.
Concentration
D.
Color of reactants
Show Answer & Explanation
Correct Answer: D
The color of reactants does not influence the chemical equilibrium; only conditions like temperature, pressure, and concentration do.
Q4
Medium
What happens to the equilibrium position when the temperature is increased in an exothermic reaction?
A.
Shifts to the left
B.
Shifts to the right
C.
Remains unchanged
D.
Increases rate of forward reaction
Show Answer & Explanation
Correct Answer: A
In exothermic reactions, increasing temperature favors the endothermic direction, hence shifts to the left.
Q5
Medium
In the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g), if the volume of the container is decreased, what is the expected change in equilibrium?
A.
Shifts to the left
B.
Shifts to the right
C.
No change
D.
Equilibrium constant increases
Show Answer & Explanation
Correct Answer: B
Decreasing volume increases pressure, which favors the side with fewer moles of gas (right side).
Q6
Medium
Which of the following changes will NOT affect the equilibrium constant (Kc) for a reaction at a given temperature?
A.
Changing reactant concentrations
B.
Changing product concentrations
C.
Changing temperature
D.
Adding an inert gas at constant volume
Show Answer & Explanation
Correct Answer: D
Adding an inert gas at constant volume does not change the equilibrium position or constant.
Q7
Medium
In the equilibrium constant expression Kc for the reaction: aA + bB ⇌ cC + dD, which of the following statements is true?
A.
Kc is dependent on temperature.
B.
Kc changes with pressure.
C.
Kc changes with concentration.
D.
Kc is the same for all reactions.
Show Answer & Explanation
Correct Answer: A
Kc is only affected by temperature; pressure and concentration do not change it.
Q8
Hard
For the equilibrium reaction A + B ⇌ C + D, if the concentration of C is increased, what will happen to the concentrations of A and B?
A.
They will increase.
B.
They will decrease.
C.
They will remain the same.
D.
They will fluctuate unpredictably.
Show Answer & Explanation
Correct Answer: B
According to Le Chatelier's principle, increasing the concentration of products (C and D) shifts the equilibrium to the left, thereby reducing the concentrations of reactants (A and B).
Q9
Hard
A reaction has an enthalpy change (ΔH) of +50 kJ/mol. What can be inferred about the equilibrium position when the temperature is increased?
A.
Equilibrium shifts to the left.
B.
Equilibrium shifts to the right.
C.
Equilibrium remains unchanged.
D.
Equilibrium shifts depending on the pressure.
Show Answer & Explanation
Correct Answer: B
For endothermic reactions (ΔH > 0), increasing the temperature shifts the equilibrium position to the right, favoring product formation.
Q10
Hard
If the Kp for a given reaction is 0.1 atm at a specific temperature, what does this indicate about the favorability of products to reactants?
A.
Products are favored.
B.
Reactants are favored.
C.
Equilibrium lies in the middle.
D.
No conclusion can be drawn.
Show Answer & Explanation
Correct Answer: B
A Kp value less than 1 indicates that at equilibrium, the concentration of reactants is greater than that of products, meaning reactants are favored.
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Equilibrium — Class 11 Chemistry Practice Questions Online
This page contains 1739 practice MCQs for the chapter Equilibrium in Class 11 Chemistry. The questions are organized by difficulty — 606 easy, 855 medium, 278 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 5 topics, giving you comprehensive coverage of the entire chapter.