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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. pH of milk is

6.5

7.5

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

Reaction stops after some time

Reaction goes backward

Reaction goes forward

Equilibrium will established

3. 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, II and III only

I and III only

I and II only

4. 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

5. 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

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

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

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

Equilibrium will not be formed

More ice will be formed

More water will be formed

Water will evaporate

7. 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

8. The relationship between Kp and Kc is give by

Kc = Kp (RT)∆n

Kp = Kc (RT)-∆n

Kp = Kc (RT)∆

Kp = Kc (RT)∆n

9. Addition of CH3COOH and CH3COONa gives in water

Standard solution

Buffer solution

Acidic buffer solution

Both b and c

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

Law of mass action

Lowery Bronsted concept

Le – Chatelier’s principle

11. A basic Buffer solution can be prepared by mixing

Weak acid and its slat with strong base

Strong base and its salt with weak acid

Weak base and its salt with strong acid

Strong acid and its slat wit weak base

12. Kc > Products / Reactants favours

Forward reaction

Reaction completed

Equilibrium

Backward reaction

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

None of these

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

The reaction stops completely

HI dissociation stops

14. Which pH is considered as basic?

15. Idea of PH and POH was put forward by

Chadwiick

Einstein

Gibbs

Sorenson

16. 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] = [B]

[A] < [B]

[A] > [C]

[B] = [C]

17. Which of the following is more acidic?

Lemons

Bananas

Bread

Apples

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

Favour the decomposition of N₂O₄

Favour the formation of N₂O₄

Stop the reaction

Not alter the equilibrium

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

None of these

Increase in concentration of one of the products

Removal of one of the products regularly

Increase in concentration of one of the reactants

20. Preparation of buffer solution can be done by mixing

Strong acid and its salt with weak base

Weak acid and its salt with weak base

Weak base and its salt with strong acid

Strong base and its salt with weak acid

21. What is the relationship between kp and kc?

kp = kc (RT)-∆n

kp = kc (RT)∆n

kc = kp (P)-∆n

Kc - kp (RT)∆n

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

More than 7

No effect

Less than 7

Equal to 7

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

Impurity

Pressure

Concentration

Temperature

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

Water evaporates

Equilibrium is not disturbed

More ice is formed

More water is formed

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

Equal volumes of N₂ and H₂ are reacting

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

The reaction has stopped

Equal masses of N₂ and H₂ are reacting

Page 2 of 3

26. Which of the following gives a basic buffer?

NaCl + CH₃ COOH

NH₄OH + NH₄Cl

NaOH + CH₃ COONa

NaOH + NaCl

27. PH of human blood is

7.50

7.80

7.00

7.35

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

Weak acid and its salt with a strong base

Strong acid and strong base

Weak base and its salt with a strong acid

Weak acid and strong base

29. 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

30. The state of equilibrium refers to

State of inertness

Stationary state

State or rest

Dynamic state

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

Constant Reaction

Irreversible Reaction

Reversible Reaction

Decomposition Reaction

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

Lower side

Optimum side

Higher side

Constant

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

Law of active mass

Law of mobile equilibrium

All of these

Law of mass action

34. Conjugate base of a very weak acid is

Strong base

Salt

Do not ionize

Weak base

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

Solids

Stable

At very high temperature

Unstable

36. Solubility of any salt can be determined from

Ksp

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

Product side

Reactant side

Remains unchanged

Fluctuate

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

Equilibrium constant changes

Rates of the forward and backward reactions change

Concentrations of the reactants and products continue to change

Reactants and products keep reacting

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

3.6 x 10¯⁵

7.2 x 10¯⁶

3.6 x 10¯⁶

4 x 10¯⁴

40. 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

Law of conservation of energy

None of all

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

0.25

1.0

3.0

0.5

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

Low temperature and high pressure

High temperature and low pressure

High temperature and high pressure

Low temperature and low pressure

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

Pressure

Temperature

None of these

Catalyst

44. 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

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

Chemical equilibrium

Dynamic equilibrium

None of all

Static equilibrium

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

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.

Conversion of A to B is only 50% complete

Only 10% conversion of A to B has taken place

47. 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

0.282

0.0796

0.0199

1.99

48. Reaction which proceed in both the directions is called

Non spontaneous

Reversible

Spontaneous

Irreversible

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

0.4 mole of CH3COOH with 0.4 mole of NaOH

0.4 mole of NH3 with 0.2 mole of HCl

0.2 mole of NaCl with 0.2 mole of HNO3

0.0002M HCl

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

Both a and b

Individually

Simultaneously

None

Page 3 of 3

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

Depends on the concentration of one of the products at equilibrium

Depends on the initial concentration of the reactants

Is not characteristic of the reaction

Does not depend on the initial concentrations of reactants

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

Not produce any change in Kc

Decrease the value of equilibrium constant

Double the value of Kc

Produce some increase in Kc

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

Amounts of A₂ and B₂

Total pressure

Catalyst

Temperature

54. Who studied the effect of temperature on equilibrium?

Vant Hoff

Arrhenius

Lewis

Van der Waal

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

Brine

Solution of CuSO4

Glue

Blood

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

Law of Mass Action

Law of Equilibrium

None of these

Law of reaction

57. Units of Kc is

Moles² dm⁺⁶

Kc may or may not have units

Moles⁺² dm¯⁶

Moles¯² dm⁺⁶

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

10¯¹⁴

10¯¹⁰

10¹⁰

10¯²⁰

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

Randomly

Slowly

Fast

Moderately

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

K = 10¯²

K = 10⁰

K = 10³

K = 10

61. Temperature for preparation of SO₃ is

400 °C

200 °C

600 °C

400 – 500 °C

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

Dissociation constant for an acid

Dissociation constant

Common ion effect

Solubility product

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

Na₂SO₄

Fecl₃₋

NaCl

Na₂CO₃

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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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