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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.
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Chemistry Chemical Equilibrium Practice Test Online With Explanation

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Page 1 of 3

Chemistry

1. The relationship between Kp and Kc is give by

Kp = Kc (RT)∆

Kp = Kc (RT)∆n

Kp = Kc (RT)-∆n

Kc = Kp (RT)∆n

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

Reactants and products keep reacting

Rates of the forward and backward reactions change

Concentrations of the reactants and products continue to change

Equilibrium constant changes

3. Kc > Products / Reactants favours

Reaction completed

Equilibrium

Forward reaction

Backward reaction

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

Not alter the equilibrium

Favour the formation of N₂O₄

Stop the reaction

Favour the decomposition of N₂O₄

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

Total pressure

Amounts of A₂ and B₂

Catalyst

Temperature

6. 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

I and III only

II and III only

I, II and III only

I and II only

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

K = 10³

K = 10⁰

K = 10¯²

K = 10

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

More water will be formed

More ice will be formed

Equilibrium will not be formed

Water will evaporate

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

Removal of one of the products regularly

None of these

Increase in concentration of one of the products

Increase in concentration of one of the reactants

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

Depends on the initial concentration of the reactants

Is not characteristic of the reaction

Depends on the concentration of one of the products at equilibrium

Does not depend on the initial concentrations of reactants

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

Blood

Solution of CuSO4

Brine

Glue

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

Irreversible Reaction

Constant Reaction

Reversible Reaction

Decomposition Reaction

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

Stable

Solids

Unstable

At very high temperature

14. 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

0.4 mole of NH3 with 0.2 mole of HCl

0.4 mole of CH3COOH with 0.4 mole of NaOH

0.0002M HCl

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

Na₂CO₃

NaCl

Na₂SO₄

Fecl₃₋

16. What is the relationship between kp and kc?

Kc - kp (RT)∆n

kc = kp (P)-∆n

kp = kc (RT)∆n

kp = kc (RT)-∆n

17. Conjugate base of a very weak acid is

Do not ionize

Weak base

Strong base

Salt

18. pH of milk is

6.5

7.5

19. 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

0.0199

0.282

1.99

0.0796

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

None

Individually

Both a and b

Simultaneously

21. Units of Kc is

Moles² dm⁺⁶

Moles⁺² dm¯⁶

Moles¯² dm⁺⁶

Kc may or may not have units

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

Randomly

Fast

Slowly

Moderately

23. 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

Remains the same

Becomes one fourth

Also be doubled

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

More ice is formed

More water is formed

Water evaporates

Equilibrium is not disturbed

25. Which of the following is more acidic?

Bananas

Apples

Lemons

Bread

Page 2 of 3

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

Law of mass action

All of these

Law of active mass

Law of mobile equilibrium

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

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

Only 10% conversion of A to B has taken place

Complete conversion of A to B has taken place

Conversion of A to B is only 50% complete

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

The reaction stops completely

None of these

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

HI dissociation stops

29. PH of human blood is

7.35

7.00

7.80

7.50

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

Equal to 7

No effect

Less than 7

More than 7

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

Dynamic equilibrium

Static equilibrium

Chemical equilibrium

None of all

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

The reaction has stopped

Equal volumes of N₂ and H₂ are reacting

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

Equal masses of N₂ and H₂ are reacting

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

Not produce any change in Kc

Produce some increase in Kc

Double the value of Kc

Decrease the value of equilibrium constant

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

Temperature

Pressure

Catalyst

None of these

35. 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

Law of mass action

None of all

Law of conservation of energy

Le – Chatelier’s principle

36. Idea of PH and POH was put forward by

Sorenson

Chadwiick

Einstein

Gibbs

37. A basic Buffer solution can be prepared by mixing

Weak base and its salt with strong acid

Strong base and its salt with weak acid

Weak acid and its slat with strong base

Strong acid and its slat wit weak base

38. Addition of CH3COOH and CH3COONa gives in water

Buffer solution

Standard solution

Acidic buffer solution

Both b and c

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

Law of Equilibrium

Law of Mass Action

Law of reaction

None of these

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

Dissociation constant

Solubility product

Common ion effect

Dissociation constant for an acid

41. Preparation of buffer solution can be done by mixing

Strong acid and its salt with weak base

Strong base and its salt with weak acid

Weak acid and its salt with weak base

Weak base and its salt with strong acid

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

Concentration

Temperature

Impurity

Pressure

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

Product side

Remains unchanged

Reactant side

Fluctuate

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

Low temperature and high pressure

High temperature and high pressure

High temperature and low pressure

Low temperature and low pressure

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

Weak acid and its salt with a strong base

Weak base and its salt with a strong acid

Strong acid and strong base

Weak acid and strong base

46. 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]

[A] < [B]

[A] = [B]

[B] = [C]

47. Temperature for preparation of SO₃ is

200 °C

400 – 500 °C

600 °C

400 °C

48. A buffer solution can be prepared by mixing

A strong acid and its salt

A weak base and its salt with strong acid

A strong acid and weak base

A weak acid and weak base

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

Reaction goes forward

Reaction goes backward

Reaction stops after some time

Equilibrium will established

50. Reaction which proceed in both the directions is called

Non spontaneous

Irreversible

Reversible

Spontaneous

Page 3 of 3

51. Which of the following gives a basic buffer?

NH₄OH + NH₄Cl

NaOH + CH₃ COONa

NaCl + CH₃ COOH

NaOH + NaCl

52. Solubility of any salt can be determined from

Ksp

53. 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

Le – Chatelier’s principle

Common on effect

Lowery Bronsted concept

Law of mass action

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

Equilibrium will not be disturbed

Water will formed

More water will be formed

More ice will be formed

55. Which pH is considered as basic?

56. 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 will have 50% product and 50% reactant 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

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

10¹⁰

10¯²⁰

10¯¹⁴

10¯¹⁰

58. Who studied the effect of temperature on equilibrium?

Arrhenius

Lewis

Vant Hoff

Van der Waal

59. The state of equilibrium refers to

State or rest

Stationary state

Dynamic state

State of inertness

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

4 x 10¯⁴

3.6 x 10¯⁶

3.6 x 10¯⁵

7.2 x 10¯⁶

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

Constant

Optimum side

Lower side

Higher side

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

0.25

1.0

3.0

0.5

63. 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

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Malik TahirLast Updated: October 14, 2025

Chemistry Chemical Equilibrium Online Mcqs Test

Important Chemistry Chemical Equilibrium Question and Answer

Chemistry Chemical Equilibrium Practice Test Online With Explanation

Chemistry

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