Equilibrium – Multiple Choice Questions

Q1. What is the molar solubility (s) of Ba3(PO4)2 in terms of Ksp?

  1. s = Ksp1/2      
  2. s = Ksp1/5     
  3. s = [Ksp/27]1/5    
  4. s = [Ksp/108]1/5     

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Q2. Which of the following is true about equilibrium processes?

  1. Rate of forward as well as that of backward reaction is independent of concentrations at given temperature.
  2. Rate of only backward reaction increases as the concentration of the reactant increases at a given temperature
  3. Rate of forward reaction increases as the concentration of the reactant increases at a given temperature
  4. Rate of both forward and backward reaction increase as the concentration of reactant is increased at a given temperature

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Q3. Which of the following is true about a 0.10 M solution of a weak acid (HX)?

  1. [X] = 0.10 M
  2. pH = 1
  3. [HX] > [H+]
  4. [H+] = 0.10 M

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Q4. Which one of the following is a weak acid?

  1. HNO3
  2. HI
  3. HF
  4. HClO3

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Q5. Which of the following statements is correct for a reversible process in a state of equilibrium? 

  1. ∆G = – 2.30RT log K
  2. ∆G = 2.30 RT log K
  3. ∆G° = -2.30 RT log K
  4. ∆G° = 2.30 RT log K

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Q6. Which of the following statements can be made about the equilibrium constant (K)?

  1. It always remains the same at different reaction conditions.
  2. It increases if the concentration of one of the products is increased.
  3. It changes with changes in the temperature.
  4. It may be changed by the addition of a catalyst.

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Q7. Solubility of BaCl2 if Ksp is 10-6 at 25 °C is

  1. 10-3 M
  2. 6.3 × 10-3 M
  3. 10-6 M
  4. Cannot be predicted

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Q8. One mole of N2 and 3 moles of H2 are mixed in a litre flask. If 50% of N2 is converted into ammonial by the reaction, N2(g) + 3 H2(g) → 2 NH3 (g) then the total number of moles of gas equilibrium will be

  1. 1
  2. 1.5
  3. 2
  4. 3

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Q9. The solubility product expression for silver(I) sulphide, using x to represent the molar concentration of silver(I) and y to represent the molar concentration of sulphide, is formulated as:

  1. x2y
  2. xy2
  3. x2y2
  4. xy3

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Q10. The conjugate base of NH3 is

  1. NH4+
  2. NH2
  3. NH2-
  4. NH

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Q11. Which of the following solutions has the lowest pH at 25oC?

  1. 0.2 M sodium hydroxide
  2. 0.2 M acetic acid
  3. 0.2 M ammonia
  4. 0.2 M benzoic acid

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Q12. A compound having molecular formula NH2CH2COOH is expected to behave

  1. Only as acid
  2. Only as base
  3. Both acid and base
  4. Neither acid nor base

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Q13. For the reversible reaction :

N2(g) + 3H2(g)⇌ 2 NH3(g) + heat

The equilibrium shifts in forward direction :

  1. By increasing the concentration of NH3(g)
  2. By decreasing the pressure
  3. By decreasing the concentration of N2(g) and H2(g)
  4. By increasing pressure and decreasing temperature

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Q14. What is the Ksp expression for lead (II) chloride?

  1. [Pb2+][Cl]2
  2. [Pb+][Cl]2/[PbCl2]
  3. [Pb2+]2[Cl]
  4. [Pb22+][Cl]2

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Q15. Which one of the following is correct for a solution in which [H+] = 10-8 M?

  1. 8, basic
  2. 6, basic
  3. -6, basic
  4. -8, neutral

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Q16. Which of the following is not a case of physical equilibrium?

  1. NH3(aq) → NH4OH
  2. H2O(s)  → H2O(g)
  3. H2O(s)  → H2O(l)
  4. CO2 (g) → CO2(aq)

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Q17. The pH of a 0.02 M solution of an unknown weak acid is 3.7. What is the pKa of this acid?

  1. 5.7
  2. 4.9
  3. 3.2
  4. 2.8

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Q18. The equilibrium constant expression depends on which of the following for the reversible reaction:

  1. mechanism
  2. stoichiometry and mechanism
  3. the quantities of reactants and products initially present
  4. temperature (Level-M)

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Q19. In which of the following reaction can equilibrium be attained?

  1. Reversible reaction
  2. Irreversible reaction
  3. Cyclic reaction
  4. Decomposition reaction

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Q20. Which aqueous solution will have the lowest pH value?

  1. 0.1 M HCl
  2. 0.10 M H2CO3
  3. 0.10 M NaOH
  4. 0.10 M NH3

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Q21. Which salt is not derived from a strong acid and a strong soluble base?

  1. AgCl
  2. NaNO3
  3. KCl
  4. NaCl

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Q22. The pH of a solution is 4.80. What is the concentration of hydroxide ions in this solution?

  1. 4.2 x 10-9 M
  2. 1.6 x 10-5 M
  3. 3.6 x 10-12 M
  4. 6.3 x 10-10 M

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Q23. Which one of the following can act as Bronsted acid as well as Bronsted Base?

  1. Na2CO3
  2. OH
  3. HCO3
  4. NH3

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Q24. The process based upon Henry’s law is

  1. Dissolution of gases in liquid at high pressure
  2. Dissolution of gases and its solution in liquid at high pressure
  3. Intermixing of gases into each other
  4. None of the above

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Q25. A mixture of  NH4Cl and NH4OH shows no change in pH upon addition small amount of HCl. This is because it is

  1. A neutral solution
  2. An acidic solution due to presence of NH4Cl
  3. A buffer
  4. A basic solution due to presence of NH4OH

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Q26. Which of the following correctly represents conjugate acid-base pair?

  1. BF3, NH3
  2. HCl, NaOH
  3. NH3, H2O
  4. HCl, Cl

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Q27. A mixture of CH3COOH and CH3COONa behaves as

  1. Acidic buffer
  2. Basic buffer
  3. Neutral buffer
  4. Ionic buffer

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Q28. Which of the following characterizes equilibrium?

  1. Dynamic nature
  2. Requires a closed system
  3. Can be physical or chemical
  4. All of the above

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Q29. When in a saturated solution of NaCl, HCl is passed, pure precipitate of NaCl is formed. This is due to the fact:

  1. That solubility of NaCl decreases
  2. That HCl is highly soluble in water
  3. That the ionic product of NaCl exceeds the solubility product of NaCl.
  4. That HCl is strong acid

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Q30. pH of a buffer solution is

  1. 1
  2. 7
  3. 9
  4. Varies with the type of buffer

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Q31. In a sample of pure water, only one of the following statements is always true at all conditions of temperature and pressure.

  1. [H3O+] = 1.0 x 10-7 M
  2. [OH] = 1.0 x 10-7 M
  3. [OH] = 1.0 x 10-14 M
  4. [H3O+] = [OH]

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Q32. Which of the following is a Lewis base?

  1. NaOH
  2. BF3
  3. NH3
  4. AlCl3

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Q33. A 0.10 M solution of a weak acid, HX, is 0.059% ionized. Evaluate Ka for the acid.

  1. 3.8 x 10-9
  2. 3.5 x 10-8
  3. 7.0 x 10-6
  4. 4.2 x 10-6

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Q34. The solubility product expression for tin(II) hydroxide, Sn(OH)2, is

  1. [Sn2+][OH]
  2. [Sn2+]2[OH]
  3. [Sn2+][OH]2
  4. [Sn2+]3[OH]

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Q35. Which of the following is more acidic? A solution with pH 5 or a solution with pH 3

  1. solution with pH 5
  2. solution with pH 3
  3. both are equally acidic
  4. cannot be predicted from pH values

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Q36. For a reaction, the reaction quotient, Qc > Kc, then the reaction

  1. is at equilibrium.
  2. is exothermic.
  3. will shift to right.
  4. will shift to left.

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Q37. The relationship between the molar solubility in water, s, and Ksp for the ionic solid Fe(OH)2 is

  1. Ksp = s3
  2. Ksp = 4s3
  3. Ksp = 2s2
  4. Ksp = s

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Q38. The solubility product of a sparingly soluble salt AX is 1.6 x 10-9. Its solubility in moles/litre is

  1. 5.6 x 10-6
  2. 3.1 x 10-4
  3. 2 x 10-4
  4. 4 x 10-5

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Q39. For HF, pKa = 3.45. What is the pH of an aqueous buffer solution that is 0.1M HF (aq) and 0.300 M KF (aq)?

  1. 11.03
  2. 2.97
  3. 3.93
  4. 10.07

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Q40. Consider the following solubility data for various chromates at 25 °C.

Salt    Ksp
Ag2CrO49.0 x 1012
BaCrO42.0 x 10 10
PbCrO41.8 x 1014

The chromate that is the most soluble in water at 25 °C on a molar basis is:

  1. Ag2CrO4
  2. BaCrO4
  3. PbCrO4
  4. none of these

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