Chemistry Chemical Equilibrium MCQs Chapter 8 Class 11 - PLS Academy

Chemistry Chemical Equilibrium MCQs – Chapter 8 Class 11

Chemistry Chemical Equilibrium is an important chapter of Class 11 Chemistry and plays a significant role in FSc Part-I exams and entry test preparation. MCQs from this chapter are frequently included in MDCAT, NUMS, AKU, NUST, UET ECAT, and board examinations. This chapter covers key topics such as dynamic equilibrium, equilibrium constant, Le Chatelier’s principle, factors affecting equilibrium, and applications of chemical equilibrium in reactions.

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Created on February 10, 2022 By Ali Durrani

Chemistry Ch 8 Class 11 Chemical Equilibrium

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1 / 68

For a reversible reaction to reach an equilibrium state the reaction should be carried out in:

Glass vessel

Iron vessel

Open vessel

Closed vessel

2 / 68

A system at equilibrium can be disturbed by:

NTS 2013
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Concentration change

B) Pressure change

C) Temperature

D) All of the above

3 / 68

For the equilibrium reaction 2 NO2 N2O4 (g) + 61 kJ, increase of temperature would:

NTS 2017
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Favour the formation of N2O4

B) Favour the decomposition N2O4

C) No effect on equilibrium

D) Stop the reaction

4 / 68

Le-Chatelier Principle is about

PMC Sample 3
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Reaction Mixture

B) Reactants

C) Equilibrium Mixture

D) Products

5 / 68

When 18 x 10-3 moles/dm3 of acetic acid react with 22 x 10-3 moles/dm3 of ethyl alcohol to form 40 x 10-3 moles/dm3 of ethyl acetate and 40 x 10-3 moles/dm-3 of water. Find the value of equilibrium constant (kc):

NTS 2010
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 4.04

B) 3.14

C) 3.04

D) 2.02

6 / 68

The value K for H2(g) + CO2(g) H2O(g) + CO(g) is 1.80 at 1000 C. If 1.0 mole of each H2 and CO2 are placed in 1 litre flask, the final equilibrium concentration of CO at 1000 C will be:

NTS 2017
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 0.295 M

B) 0.385 M

C) 0.531 M

D) 0.473 M

7 / 68

The Kcunits for the reaction N2(g) + 3H2(g) -> 2NH3(g) are:

NUMS 2019 Reconduct
Chemistry
Chemical Equilibrium
Elimination Tool:

A) mol-1dm6

B) mol-2dm3

C) mol-2dm6

D) mol-1dm3

8 / 68

Concentration of reactants and products are expressed as Moles per unit _______.

PMC Sample 1
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Area

B) length

C) Volume

D) None of these

9 / 68

For a gaseous phase reaction, when number of moles of reactants and products are equal:

PMC 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) The values of Kp and Kc are different

B) The value of Kp is greater than Kc

C) The value of Kc is greater than Kp

D) The values of Kp and Kc are the same

10 / 68

For a reaction 2A + B ⇌ C + D the active mass of B is kept constant and that of A is tripled. It is observed that the rate of reaction:

NTS 2013
Chemistry
Chemical Equilibrium
Elimination Tool:

A) decreases three times

B) decreases nine times

C) increases six times

D) increases nine times

11 / 68

The Ksp of AgCl is 2.0 x 10^-10-1010 mol2dm-6 . The maximum concentration of Ag+ ions:

NUMS 2015
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 2.0 x 10-10mol.dm-6

B) 1.41 x 10-5mol.dm-3

C) 1.0 x 10-5mol.dm-3

D) 4.0 x 10-20mol.dm-3

12 / 68

If Kc = 1, then reaction is:

At equilibrium

complete

Moves in forward direction

None of these

13 / 68

Which of the following has the highest value of pKa?

NUMS 2019 Reconduct
Chemistry
Chemical Equilibrium
Elimination Tool:

A) CH3- CH2OH

B) CI – CH2- CH2OH

C) F3C – CH2- OH

D) CH3- CH(CH3) – CH2OH

14 / 68

For a gaseous reaction, the increase in pressure will shift the equilibrium in a direction:

NUMS 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Decreased concentration

B) Increased concentration

C) Decreased volume

D) Increased volume

15 / 68

If the ratio of initial concentration of the reagents is greater than the Kc then:

NTS 2011
Chemistry
Chemical Equilibrium
Elimination Tool:

A) The reaction will shift towards the reverse direction

B) More quantity of products is obtained

C) The ratio increases to the value of Kc

D) Equilibrium has been attained

16 / 68

In a exothermic process, forward direction reaction is favored by:

Increase in temperature

Decrease In temperature

) Increase and decrease repeatedly

None of these

17 / 68

If the value of ‘Kc’ is very large then, it shows that ______ completed.

NUMS 2018
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Forward reaction

B) Reverse reaction

C) Equilibrium is maintained

D) Kcis moderate

18 / 68

If Kc < 1, then the reaction proceeds:

Forwards

Backwards

Is at Equilibrium

None of these

19 / 68

Which statement about the following equilibrium is correct?

2SO2 (g) + O2(g) ⇌ 2SO3(g) ΔH= – 395 KJ/ mole

NTS 2019
Chemistry
Chemical Equilibrium
Elimination Tool:

A) The value of Kp falls, with a rise in temperature

B) The value of Kp falls with an increase in pressure

C) The value of Kc is equal to Kp

D) The value of Kc remains constant with rise in temperature.

20 / 68

Buffer solution of every liquid is

Same

Different

Depends upon pH

None of these

21 / 68

Buffer capacity depends upon

pOH

Remains same

Both a and b

22 / 68

23 / 68

The solubility product of AgCl is 2.0×10-10 mol-2 dm-6. The maximum concentration of Ag+1 ions in the solution is:

NTS 2019
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 2.0×10-12 mol dm-3

B) 1.41x 10-5 mol dm-3

C) 1.0×10-12 mol dm-3

D) 2.5×10-10 mol dm-3

24 / 68

Precipitation occurs when the product of ionic concentrations is:

NUMS 2019 Reconduct
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Greater than Ksp

B) Less than Ksp

C) Equal to Ksp

D) Equal to unity

25 / 68

Common Ion effect is useful application in?

NTS 2015 SMBBMC
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Qualitative salt analysis

B) quantitative salt analysis

C) both A and B

D) none of the above

26 / 68

By which of the following factors, equilibrium state is attained earlier?

NUMS 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Temperature

B) Pressure

C) Concentration

D) Catalyst

27 / 68

If the value of Kc is large than the ratio (products)/(reactants), the reaction:

Is at equilibrium

Is not at equilibrium

The reaction moves in the forward direction

The direction will move in the reverse direction

28 / 68

A solution has pH of 10. What is the value of [OH-]?

10^4

10^-4

10^6

10^-6

29 / 68

1.8 x 10 -5 is the dissociation constant of:

NTS 2016 SMBBMC
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Formic acid

B) Acetic acid

C) Chloroacetic acid

D) Hydrocyanic acid

30 / 68

Law of mass action was derived by:

NUMS 2014
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Newton

B) CM Guldberg

C) P Waage

D) CM Guldberg and P Waage

31 / 68

For, the reaction:

N2 + 3H2 ⇌ 2NH3

The production of NH3 will be favored at:

NTS 2010
Chemistry
Chemical Equilibrium
Elimination Tool:

A) High pressure and catalyst

B) Low pressure only

C) Low pressure and catalyst

D) High pressure only

32 / 68

The following changes to the system at equilibrium have no effect on Kc except:

NUMS 2017
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Increasing reactant concentrations

B) Equal number of reactant and product gas molecules

C) Increasing temperature

D) Using a catalyst

33 / 68

In Exothermic Reactions heat is _______

PMC Sample 3
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Taken in

B) Give out to surroundings

C) Neither given nor lost

D) None of these

34 / 68

For an equilibrium change involving gaseous phase, the forward reaction is first order while the reverse reaction is second order. The unit of Kp for the forward equilibrium is:

NTS 2019
Chemistry
Chemical Equilibrium
Elimination Tool:

A) atm

B) atm2

C) atm-1

D) atm-2

35 / 68

In the reaction;

H2 + CO2 H2O + CO

The decrease in the concentration of reactants and products cause the equilibrium to shift:

NUMS 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Towards left

B) Towards right

C) Nothing happens to the equilibrium

D) Equilibrium will shift towards both the directions

36 / 68

37 / 68

Purification of table salt (NaCl) by passing HCl gas through its saturated aqueous solution is an example of:

PMC 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Law of mass action

B) Hess’s law

C) Common ion effect

D) Henry’s law

38 / 68

Le Chatelier’s principle explains effect of all of the following except

Pressure

Temperature

Concentration

Time

39 / 68

In a reversible reaction, catalyst lowers the action energy of the:

NUMS 2020
Chemistry
Reaction Kinetics
Chemical Equilibrium
Elimination Tool:

A) Forward reaction

B) Reverse reaction

C) Forward as well as reverse reaction

D) Forward reaction but increases that of the reverse reaction

40 / 68

When the number of moles of reactants and products are equal in reversible reactions which parameter would not affect at equilibrium?

NUMS 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Temperature

B) Pressure

C) Volume

D) Catalyst

41 / 68

What is correct relation between Kw, Kb and Ka?

Kw=Ka/ Kb

Kw=Kb/ Ka

Kw=Ka*Kb

Kw=Kb-Ka

42 / 68

The change in concentration of reactant or product per unit time is called:

NTS 2016 DUHS & JSMU
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Rate constant

B) Rate of reaction

C) Rate equation

D) Rate law

43 / 68

A solution having pH = 0 is

Strongly basic

Weakly basic

Neutral

Strongly acidic

44 / 68

Which of the following reaction has greater Kp than Kc?

PMC 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 2NO + Cl2 2NOCl

B) 2SO2 + O2 2SO3

C) 2NOCl 2NO + Cl2

D) N2 + 3H2 2NH3

45 / 68

For which one of the following gaseous equilibrium will an increase in pressure increase the yield of the product:

NTS 2014
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 2HI ⇌ H2 + I2

B) 2SO2 + O2 ⇌ 2SO3

C) H2O + CO ⇌ H2+ CO2

D) H2 + Br2 ⇌ 2HBr

46 / 68

For the following exothermic reaction, a decrease in temperature will shift the equilibrium towards: 2NO (g) + O2(g) -> 2NO2 (g)

NTS 2018
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Left

B) The point of equilibrium

C) Both directions

D) Right

47 / 68

A reaction with a tendency of occurring in forward and backward direction simultaneously is termed as

PMC Sample 1
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Irreversible

B) Unidirectional

C) Multidirectional

D) Reversible

48 / 68

49 / 68

A correct formula must:

NTS 2017
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Be balanced with proper coefficients

B) Always have subscripts

C) Always conform to the valency rules

D) Always conforms to the law of multiple proportions

50 / 68

A reaction with a tendency of occurring in forward and backward direction simultaneously is termed as

PMC Sample 2
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Irreversible

B) Unidirectional

C) Multidirectional

D) Reversible

51 / 68

The equation N2(g)+ 3H2(g)⇋ 2NH3(g)represents:

PMC 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Contact process

B) Haber’s process

C) Solvay process

D) Avogadro’s Law

52 / 68

Equilibrium constant has no units if?

The number moles are same on both sides of the chemical equation

The number of moles is different on both sides.

The number of moles is greater in the product

If the rate of reaction is constant

53 / 68

54 / 68

If 4.6 gm of ethyl alcohol and 6.0 gm of acetic acid is kept at a constant temperature until equilibrium was established, 2.0 gm of unused acetic acid were present. What is the Kc?

NTS 2016 SMBBMC
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 2.0

B) 3.0

C) 4.0

D) 5.0

55 / 68

At equilibrium, which of the following reactions is not affected by pressure?

NUMS 2016
Chemistry
Chemical Equilibrium
Elimination Tool:

A) ½ N2(g) + ½ O2 (g)⇌ NO(g)

B) PCl5(g) ⇌ PCl3(g) + Cl2(g)

C) 2NO2 (g) ⇌ N2O4(g)

D) SO2Cl2(g) ⇌ SO2(g) + Cl2(g)

56 / 68

A chemical engineer wants to use the Haber process in order to produce ammonia as raw material for fertilizers. Which of the following parameters must the chemical engineer AVOID in order to obtain the maximum yield of ammonia?
N2(g) + 3H2(g) -> 2NH3(g) ΔH0 = -92.6 kJ/mol

NUMS 2019 Cancelled
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Increase the temperature

B) Use a catalyst

C) Adding more nitrogen gas

D) Increase the pressure

57 / 68

In the reaction, 2SO2 (g) + O2 ⇌ 2SO3 (g) ∆H= +X cal most favorable conditions of temperature and pressure for a greater yield of SO2 are:

NTS 2014
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Low temperature and low pressure

B) High temperature and low pressure

C) High temperature and high pressure

D) Low temperature and high pressure

58 / 68

How will the equilibrium of the following reaction be affected if additional nitrogen is added?

N2(g) + 3H2(g)⇌ 2NH3(g)

NTS 2015 DUHS and JSMU
Chemistry
Chemical Equilibrium
Elimination Tool:

A) It will be shifted to the right.

B) It will be shifted to the left.

C) it will be unaffected.

D) The effect on the equilibrium cannot be determined without more information.

59 / 68

A very small value of ‘Kc’ for a reaction at equilibrium indicates:

NUMS 2018
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Very small amount of reactants

B) Very small amount of products

C) The rate of backward reaction is greater than that of the forward one

D) The rate of forward reaction is greater than that of the backward one

60 / 68

Buffer solution is a solution which resists change in?

Concentration

Number of moles

Rate of reaction

61 / 68

The Haber Process is used to produce ammonia commercially according to the following equilibrium: N2(g) + 3H2g = 2NH3g + energy Which of the following conditions will produce the highest yield of ammonia?

Increase temperature and increase pressure

Increase temperature and decrease pressure

Decrease temperature and increase pressure

Decrease temperature and Decrease pressure

62 / 68

1 mole of N2O4 (g) was placed in an empty 1 dm^3 container and allowed to reach equilibrium according to the following equation:

N2O4(g) 2NO2(g)

At equilibrium, x mole Of N2O4 (g) had dissociated. What is the value of the equilibrium constant, Kc, at the temperature of the Experiment?

NTS 2016 SMBBMC
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 2x / ( 1 – x)

B) 4×2 / (1 – x)2

C) 2x / (1 – x )2

D) 4×2 / (1 – x)

63 / 68

According to the law of mass action, “The rate of chemical reaction” is proportional to the:

NTS 2010
Chemistry
Chemical Equilibrium
Elimination Tool:

A) The amount of product formed

B) Product of the molar concentration of reactants

C) The initial concentration of reactants

D) Catalyst

64 / 68

In a reaction:

A+B 2C

When equilibrium was attained, the concentration was

[A] = [B] = 4 moles/dm3

[C]= 6 moles/dm3
The equilibrium constant Kc of this reaction is:

NTS 2011
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 1.25

B) 2.25

C) 3.25

D) 2.75

65 / 68

Consider the following reaction

N2(g) + O2(g) 2NO (g) Kc- 0.1 at 2000 C

If the original concentration of N2 and O2 were 0.1 M each. Calculate the concentrations of NO at equilibrium.

NTS 2016 DUHS & JSMU
Chemistry
Chemical Equilibrium
Elimination Tool:

A) 0.028 M

B) 0.0012 M

C) 0.18 M

D) 0.0018 M

66 / 68

At equilibrium the concentration of reactants and product become:

NUMS 2020
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Zero

B) Equal

C) Constant

D) Infinite

67 / 68

If concentration of OH- Ions Is 0.1 molar. What Is the pH of the solution?

68 / 68

Which of the following factor(s) affect a reversible chemical reaction in accordance with the Le – Chatelier Principle?

NUMS 2019 Reconduct
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Pressure

B) Temperature

C) Concentration

D) Pressure, concentration and temperature

Your score is

The average score is 61%

Importance of Chemical Equilibrium MCQs

A strong understanding of chemical equilibrium helps students predict the direction of reactions and calculate equilibrium constants. Exams often include MCQs on Le Chatelier’s principle, equilibrium calculations, and the effect of concentration, temperature, and pressure on reactions. Practicing chapter-wise MCQs improves conceptual clarity, problem-solving skills, and confidence for competitive exams.

Effective Strategy for Free Preparation

For effective preparation, students should revise equilibrium formulas and concepts regularly, practice numerical problems step by step, and solve topic-wise MCQs consistently. Attempting free tests and past paper questions helps identify important concepts and repeated exam patterns. PLS Academy provides structured MCQs and free resources to support Chemistry Chemical Equilibrium preparation and other Class 11 Chemistry chapters.

JazakAllah

Comments

4 responses to “Chemistry Chemical Equilibrium MCQs Chapter 8 Class 11”

M.Anas Nazim

July 14, 2022

MCQ no 10 is wrong correct answer is D (increasing presure and decreasing temprature)
1. Ali Durrani
  
  July 15, 2022
  
  JazakAllah we will review IA
Summaira

August 26, 2022

Yesterday I had attempted a mock test and answer of two mcqs was wrong in the key
1. Ali Durrani
  
  August 26, 2022
  
  Kindly point out MCQs we will update IA