Chemistry Chemical Equilibrium Online Mcqs Test

Malik TahirLast Updated: October 14, 2025

Important Chemistry Chemical Equilibrium Question and Answer

Total Questions:	63
Time Allowed:	30 Minutes
Total Marks:	63
How to Attempt Test:	Please choose the right Option in MCQ-type question.
Test Helpful For:	Chemistry Test ECAT Test MDCAT Test FPSC/PPSC/SPSC/KPPSC/BPSC/AJKPSC/NTS Chemistry Interview Question Answer

Chemistry Chemical Equilibrium Practice Test Online With Explanation

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Page 1 of 3

Chemistry

1. Solubility of any salt can be determined from

Ksp

2. Water and ice are in equilibrium at 0C° and pressure is applied at this stage, then

More ice is formed

Equilibrium is not disturbed

More water is formed

Water evaporates

3. Reaction which proceed in both the directions is called

Reversible

Irreversible

Spontaneous

Non spontaneous

4. In an exothermic reaction, a 10° rise in temperature will

Double the value of Kc

Decrease the value of equilibrium constant

Produce some increase in Kc

Not produce any change in Kc

5. Which of the following is more acidic?

Apples

Lemons

Bananas

Bread

6. In an exothermic reversible reaction increase in temp shifts the equilibrium to

Reactant side

Product side

Remains unchanged

Fluctuate

7. When rate of forward reaction is equal to rate of backward reaction, then the equilibrium established is called

Dynamic equilibrium

None of all

Chemical equilibrium

Static equilibrium

8. When pressure is applied to the equilibrium system Ice ⇌ Water? Which of the following phenomenon will happen?

More ice will be formed

More water will be formed

Equilibrium will not be formed

Water will evaporate

9. A chemical reaction A ⇌ B is said to be in equilibrium when

Complete conversion of A to B has taken place

Only 10% conversion of A to B has taken place

Conversion of A to B is only 50% complete

The rate of transformation of A to B is just equal to rate of transformation of B to A in the system.

10. When sparingly soluble salt is in equilibrium with molar concentration of its oppositely charged ion when the product is called

Common ion effect

Solubility product

Dissociation constant for an acid

Dissociation constant

11. Which of the following aqeous solution will be basic?

NaCl

Na₂CO₃

Fecl₃₋

Na₂SO₄

12. A basic Buffer solution can be prepared by mixing

Strong base and its salt with weak acid

Strong acid and its slat wit weak base

Weak acid and its slat with strong base

Weak base and its salt with strong acid

13. pH of milk is

7.5

6.5

14. Which of the following gives a basic buffer?

NH₄OH + NH₄Cl

NaOH + NaCl

NaCl + CH₃ COOH

NaOH + CH₃ COONa

15. PH of human blood is

7.50

7.80

7.00

7.35

16. Conjugate base of a very weak acid is

Salt

Weak base

Strong base

Do not ionize

17. Units of Kc is

Moles¯² dm⁺⁶

Moles⁺² dm¯⁶

Kc may or may not have units

Moles² dm⁺⁶

18. The relationship between Kp and Kc is give by

Kp = Kc (RT)∆n

Kp = Kc (RT)∆

Kc = Kp (RT)∆n

Kp = Kc (RT)-∆n

19. The rate of chemical reaction is directly proportional to the active mass of reactant this statement is known as ___________

Law of Mass Action

None of these

Law of reaction

Law of Equilibrium

20. AgCl dissolved with cone (2 x 10¯²) Ksp will be

3.6 x 10¯⁶

4 x 10¯⁴

3.6 x 10¯⁵

7.2 x 10¯⁶

21. If a buffer solution of higher PH than seven is to be made we use

Strong acid and strong base

Weak acid and strong base

Weak base and its salt with a strong acid

Weak acid and its salt with a strong base

22. The product of [0H¯][H⁺] at 25C° is

10¯¹⁰

10¹⁰

10¯¹⁴

10¯²⁰

23. Le-Chatelier’s principle is sometime known as

All of these

Law of mass action

Law of mobile equilibrium

Law of active mass

24. The state of equilibrium refers to

State of inertness

Dynamic state

State or rest

Stationary state

25. Idea of PH and POH was put forward by

Gibbs

Chadwiick

Sorenson

Einstein

Page 2 of 3

26. In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled then the equilibrium constant will

Be halved

Becomes one fourth

Also be doubled

Remains the same

27. For the reaction 2A(g) + B(g) ⇌ 3C(g) + D(g) two moles each of A and B were taken into a flask. The following must always be true when the system attained equilibrium

[A] > [C]

[B] = [C]

[A] < [B]

[A] = [B]

28. In reversible reactions, if the forward reaction occur very fast then reactant (s) is (are) __________

Unstable

Solids

Stable

At very high temperature

29. Which one of the following is a buffer solution?

Blood

Glue

Brine

Solution of CuSO4

30. By the addition of base in water pH will be

No effect

Equal to 7

Less than 7

More than 7

31. A buffer solution can be prepared by mixing

A strong acid and its salt

A weak base and its salt with strong acid

A weak acid and weak base

A strong acid and weak base

32. The equilibrium constant in a reversible chemical reaction at a given temperature

Depends on the concentration of one of the products at equilibrium

Does not depend on the initial concentrations of reactants

Is not characteristic of the reaction

Depends on the initial concentration of the reactants

33. In reversible reaction the changes in forward and backward reaction occur _________

Both a and b

Individually

None

Simultaneously

34. The rate at which a substance reacts is directly proportional to its active mass and the rate of reaction is directly proportional to the product of the active mass of reacting substances is known as

Le – Chatelier’s principle

Law of conservation of energy

None of all

Law of mass action

35. Temperature for preparation of SO₃ is

400 – 500 °C

600 °C

400 °C

200 °C

36. Which set of solutes will form a buffer when dissolved in water to make 1 litter of solution?

0.2 mole of NaCl with 0.2 mole of HNO3

0.0002M HCl

0.4 mole of NH3 with 0.2 mole of HCl

0.4 mole of CH3COOH with 0.4 mole of NaOH

37. Which statements are correct for a reaction at equilibrium?
(I) The forward and reverse reactions both continue
(II) The rates of the forward and reverse reactions are equal
(III) The concentrations of reactants and products are equal

II and III only

I and II only

I and III only

I, II and III only

38. Two moles of HI was heated in a sealed tube at 440°C till the equilibrium was reached. HI was found to be 22% decomposed. The equilibrium constant for dissociation is

0.0796

1.99

0.0199

0.282

39. When H₂ and I₂ are mixed and equilibrium is attained, then

The reaction stops completely

Amount of HI formed is equal to the amount of H₂ dissociated

None of these

HI dissociation stops

40. Addition of CH3COOH and CH3COONa gives in water

Standard solution

Buffer solution

Acidic buffer solution

Both b and c

41. Synthesis of ammonia by Habor process is an example of ___________

Irreversible Reaction

Reversible Reaction

Constant Reaction

Decomposition Reaction

42. For equilibrium 2NO₂(g) ⇌ N₂O₄(g) + 14.6 kcal increase of temperature would

Not alter the equilibrium

Stop the reaction

Favour the decomposition of N₂O₄

Favour the formation of N₂O₄

43. The equilibrium will shift towards right by increasing ___________ of reactants

Temperature

Concentration

Pressure

Impurity

44. When pressure is applied to the given equilibrium ice water which of the following will happen

More ice will be formed

Equilibrium will not be disturbed

Water will formed

More water will be formed

45. In a chemical reaction N₂ + 3H₂ ⇌ 2NH₃ at equilibrium point

The reaction has stopped

Equal masses of N₂ and H₂ are reacting

Equal volumes of N₂ and H₂ are reacting

The same amount of ammonia is formed as is decomposed into N₂ and H₂

46. At start of reaction, concentration of reactants are on

Constant

Lower side

Higher side

Optimum side

47. The factor which changes equilibrium constant o the reaction A₂(g) + B₂(g) → 2 AB(g) is

Catalyst

Amounts of A₂ and B₂

Total pressure

Temperature

48. In which of the following cases, the reaction goes farthest to completion?

K = 10

K = 10³

K = 10¯²

K = 10⁰

49. The reaction 2SO₂ + 2O₂ ⇌ 2SO will be favoured by

Low temperature and low pressure

High temperature and high pressure

High temperature and low pressure

Low temperature and high pressure

50. At certain temperature, 50% of HI is dissociated into H₂ and I₂ the equilibrium constant is

1.0

3.0

0.5

0.25

Page 3 of 3

51. Chemical equilibrium is referred to as dynamic because, at equilibrium, the

Equilibrium constant changes

Concentrations of the reactants and products continue to change

Rates of the forward and backward reactions change

Reactants and products keep reacting

52. What can affect the magnitude of equilibrium constant Kp of a reversible gaseous reaction

Pressure

Temperature

None of these

Catalyst

53. If rate of concentration of reaction is equal to rate of concentration of products in reversible reaction the __________

Reaction goes backward

Reaction goes forward

Reaction stops after some time

Equilibrium will established

54. If the value of kc is very low then the forward reaction will occur __________

Randomly

Slowly

Moderately

Fast

55. Kc > Products / Reactants favours

Forward reaction

Reaction completed

Equilibrium

Backward reaction

56. Who studied the effect of temperature on equilibrium?

Van der Waal

Arrhenius

Vant Hoff

Lewis

57. Which pH is considered as basic?

58. What is the relationship between kp and kc?

kp = kc (RT)-∆n

kp = kc (RT)∆n

kc = kp (P)-∆n

Kc - kp (RT)∆n

59. Which of the following factors will favour the reverse reaction in a chemical equilibrium?

Increase in concentration of one of the products

Removal of one of the products regularly

None of these

Increase in concentration of one of the reactants

60. An equilibrium constant of 10¯⁴ for a reaction means that the reaction is

One that is very favorable and will have mostly product at equilibrium

One that is unfavourable and will not have very much product at equilibrium

The equilibrium constant only relates to the speed of a reaction and not to the amount of product formed

One that will have 50% product and 50% reactant at equilibrium

61. For a reaction H₂ + I₂ ⇌ 2HI at 721 K, the value of equilibrium constant is 50. If 0.5 moles each of H₂ and I₂ is added to the system the value of equilibrium constant will be

0.2

0.02

62. When ever a week a base is dissolved in water, it gives its conjugate acid similarly a weal acid in water products its conjugate base. The conjugate acid base pair is stated by

Common on effect

Le – Chatelier’s principle

Lowery Bronsted concept

Law of mass action

63. Preparation of buffer solution can be done by mixing

Weak base and its salt with strong acid

Strong base and its salt with weak acid

Strong acid and its salt with weak base

Weak acid and its salt with weak base

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Malik TahirLast Updated: October 14, 2025

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