Chemistry Chemical Equilibrium MCQs Chapter 8 Class 11

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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

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

2 / 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

3 / 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

4 / 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

5 / 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

6 / 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

7 / 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

8 / 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

9 / 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

10 / 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.

11 / 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

12 / 68

Buffer solution is a solution which resists change in?

Concentration

Number of moles

Rate of reaction

13 / 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

14 / 68

Le-Chatelier Principle is about

PMC Sample 3
Chemistry
Chemical Equilibrium
Elimination Tool:

A) Reaction Mixture

B) Reactants

C) Equilibrium Mixture

D) Products

15 / 68

Buffer solution of every liquid is

Same

Different

Depends upon pH

None of these

16 / 68

If Kc = 1, then reaction is:

At equilibrium

complete

Moves in forward direction

None of these

17 / 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

18 / 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

19 / 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

20 / 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

21 / 68

22 / 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

23 / 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

24 / 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

25 / 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

26 / 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)

27 / 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

28 / 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

29 / 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

30 / 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

31 / 68

What is correct relation between Kw, Kb and Ka?

Kw=Ka/ Kb

Kw=Kb/ Ka

Kw=Ka*Kb

Kw=Kb-Ka

32 / 68

A solution having pH = 0 is

Strongly basic

Weakly basic

Neutral

Strongly acidic

33 / 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

34 / 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

35 / 68

36 / 68

Buffer capacity depends upon

pOH

Remains same

Both a and b

37 / 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

38 / 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

39 / 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

40 / 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)

41 / 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

42 / 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

43 / 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

44 / 68

45 / 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

46 / 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

47 / 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

48 / 68

If Kc < 1, then the reaction proceeds:

Forwards

Backwards

Is at Equilibrium

None of these

49 / 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

50 / 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

51 / 68

52 / 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.

53 / 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

54 / 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

55 / 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

56 / 68

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

10^4

10^-4

10^6

10^-6

57 / 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

58 / 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

59 / 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

60 / 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

61 / 68

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

Increase in temperature

Decrease In temperature

) Increase and decrease repeatedly

None of these

62 / 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

63 / 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

64 / 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

65 / 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

66 / 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

67 / 68

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

68 / 68

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

Pressure

Temperature

Concentration

Time

Your score is

The average score is 61%

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

M.Anas Nazim says:

July 14, 2022 at 9:27 pm

MCQ no 10 is wrong correct answer is D (increasing presure and decreasing temprature)
- Ali Durrani says:
  
  July 15, 2022 at 8:42 pm
  
  JazakAllah we will review IA
Summaira says:

August 26, 2022 at 2:28 pm

Yesterday I had attempted a mock test and answer of two mcqs was wrong in the key
- Ali Durrani says:
  
  August 26, 2022 at 3:24 pm
  
  Kindly point out MCQs we will update IA