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ECAT Chemistry Chemical Equilibrium Test Online

Maan AliLast Updated: April 19, 2025

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

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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ECAT Chemistry Chemical Equilibrium Test

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Page 1 of 3

Chemistry

1. 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 Equilibrium

Law of reaction

2. Kc > Products / Reactants favours

Forward reaction

Reaction completed

Equilibrium

Backward reaction

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

Becomes one fourth

Be halved

Also be doubled

Remains the same

4. 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

0.0199

0.282

1.99

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

Double the value of Kc

Produce some increase in Kc

Decrease the value of equilibrium constant

Not produce any change in Kc

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

All of these

Law of mass action

Law of mobile equilibrium

Law of active mass

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

NaCl

Fecl₃₋

Na₂SO₄

Na₂CO₃

8. 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

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

Remains unchanged

Reactant side

Fluctuate

Product side

10. 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

11. Which pH is considered as basic?

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

3.6 x 10¯⁶

3.6 x 10¯⁵

7.2 x 10¯⁶

4 x 10¯⁴

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

Common ion effect

Dissociation constant

Solubility product

Dissociation constant for an acid

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

Optimum side

Lower side

Higher side

Constant

15. 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

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

Water will evaporate

Equilibrium will not be formed

More ice will be formed

More water will be formed

17. Who studied the effect of temperature on equilibrium?

Van der Waal

Vant Hoff

Arrhenius

Lewis

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

Low temperature and low pressure

Low temperature and high pressure

High temperature and high pressure

High temperature and low pressure

19. 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 mass action

None of all

Law of conservation of energy

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

Conversion of A to B is only 50% complete

Complete conversion of A to B has taken place

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

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

Water will formed

More ice will be formed

More water will be formed

Equilibrium will not be disturbed

22. Addition of CH3COOH and CH3COONa gives in water

Acidic buffer solution

Buffer solution

Both b and c

Standard solution

23. The relationship between Kp and Kc is give by

Kp = Kc (RT)∆

Kp = Kc (RT)∆n

Kp = Kc (RT)-∆n

Kc = Kp (RT)∆n

24. Preparation of buffer solution can be done by mixing

Weak acid and its salt with weak base

Weak base and its salt with strong acid

Strong acid and its salt with weak base

Strong base and its salt with weak acid

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

Reaction goes backward

Reaction goes forward

Equilibrium will established

Reaction stops after some time

Page 2 of 3

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

Equilibrium is not disturbed

More ice is formed

More water is formed

Water evaporates

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

10¯¹⁴

10¯²⁰

10¯¹⁰

10¹⁰

28. Solubility of any salt can be determined from

Ksp

29. Units of Kc is

Moles¯² dm⁺⁶

Moles² dm⁺⁶

Kc may or may not have units

Moles⁺² dm¯⁶

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

Favour the formation of N₂O₄

Not alter the equilibrium

Stop the reaction

Favour the decomposition of N₂O₄

31. What is the relationship between kp and kc?

Kc - kp (RT)∆n

kp = kc (RT)-∆n

kp = kc (RT)∆n

kc = kp (P)-∆n

32. 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, II and III only

I and II only

II and III only

I and III only

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

Both a and b

Simultaneously

Individually

None

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

Increase in concentration of one of the reactants

Increase in concentration of one of the products

Removal of one of the products regularly

None of these

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

Does not depend on the initial concentrations of reactants

Is not characteristic of the reaction

Depends on the initial concentration of the reactants

Depends on the concentration of one of the products at equilibrium

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

3.0

0.25

0.5

1.0

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

Temperature

Catalyst

None of these

Pressure

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

Weak acid and strong base

Strong acid and strong base

Weak base and its salt with a strong acid

Weak acid and its salt with a strong base

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

Less than 7

More than 7

Equal to 7

No effect

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

Temperature

Concentration

Impurity

Pressure

41. 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

42. Which of the following is more acidic?

Apples

Bread

Bananas

Lemons

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

Rates of the forward and backward reactions change

Equilibrium constant changes

Concentrations of the reactants and products continue to change

Reactants and products keep reacting

44. 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

45. 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

46. Reaction which proceed in both the directions is called

Spontaneous

Irreversible

Non spontaneous

Reversible

47. Which of the following gives a basic buffer?

NH₄OH + NH₄Cl

NaCl + CH₃ COOH

NaOH + CH₃ COONa

NaOH + NaCl

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

Temperature

Total pressure

Amounts of A₂ and B₂

Catalyst

49. A basic Buffer solution can be prepared by mixing

Strong base and its salt with weak acid

Weak base and its salt with strong acid

Weak acid and its slat with strong base

Strong acid and its slat wit weak base

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

None of these

The reaction stops completely

HI dissociation stops

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

Page 3 of 3

51. Temperature for preparation of SO₃ is

400 – 500 °C

600 °C

400 °C

200 °C

52. PH of human blood is

7.35

7.00

7.50

7.80

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

Glue

Solution of CuSO4

Brine

Blood

54. The state of equilibrium refers to

Stationary state

Dynamic state

State of inertness

State or rest

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

K = 10¯²

K = 10³

K = 10

K = 10⁰

56. 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]

57. Idea of PH and POH was put forward by

Chadwiick

Einstein

Sorenson

Gibbs

58. 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

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

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

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

Unstable

At very high temperature

Stable

Solids

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

Decomposition Reaction

Irreversible Reaction

Reversible Reaction

Constant Reaction

61. pH of milk is

6.5

7.5

62. Conjugate base of a very weak acid is

Do not ionize

Strong base

Salt

Weak base

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

Slowly

Randomly

Fast

Moderately

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Maan AliLast Updated: April 19, 2025

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ECAT Chemistry Chemical Equilibrium Test Online

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

ECAT Chemistry Chemical Equilibrium Test

Chemistry

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Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

ECAT Chemistry Chemical Equilibrium Test

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