Chemical Equilibrium

MDCAT • Chemistry

169 MCQs — Click "Reveal" to see the correct answer

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  1. 1
    UHS MDCAT 2009

    Solubility of KCIO3 can be decreased in H2O by:

  2. 2
    UHS MDCAT 2009

    Equilibrium constant Kc for H2O H+ + OH- can be written as follows:


  3. 3
    UHS MDCAT 2010

    0.1 mole of acetic acid has been dissolved per dm3 of the solution, the percentage ionization of acetic acid will be:

  4. 4
    UHS MDCAT 2010

    The Kc has following units for the reaction H2(g) + I2(g) ⇋ 2HI (g)

  5. 5
    UHS MDCAT 2011

    ‘Ka’ for an acid is higher, the stronger is the acid; relate the strength of an acid with ‘pKa’:

  6. 6
    UHS MDCAT 2011

    In 'AgCl' solution, some salt of NaCl is added, 'AgCl' will be precipitated due to:

  7. 7
    UHS MDCAT 2012

    A buffer solution is that which resists/minimizes the change in:

  8. 8
    UHS MDCAT 2012

    The formation of NH3 is a reversible and exothermic process, what will happen on cooling?

  9. 9
    UHS MDCAT 2013

    The 'pH' of human blood is:

  10. 10
    UHS MDCAT 2013

    The chemical substance, when dissolved in water, gives “H+” is called:

  11. 11
    UHS MDCAT 2014

    One mole of glucose was dissolved in 1 kg of water, ethanol, ether, and benzene separately and the molal boiling point constant of each solution was found to be 0.52, 1.75,2.16, and 2.70 in the units of / °C kg mol-1 respectively. Which of the following figures shows benzene as a solvent in solution?


  12. 12
    UHS MDCAT 2014

    What will be the pH of a solution of NaOH with a concentration of 10-3 M?

  13. 13
    UHS MDCAT 2014

    The value of equilibrium constant (Kc) for the reaction 2HF(g) ⇌ H2(g) + F2(g) is 10-13 at 2000°C. Calculate the value of Kp for this reaction:

  14. 14
    UHS MDCAT 2015

    Which one of the following is the correct presentation for Ksp?

  15. 15
    UHS MDCAT 2015

    During the manufacture of nitric acid, nitric oxide is oxidized to nitrogen dioxide.

    This reaction is given as: 2NO(g) + O2(g) ⇌ 2NO2(g) ΔH = -114 kJ/mol

    According to Le Chatelier’s Principle;

  16. 16
    UHS MDCAT 2016

    Value of Ksp for PbSO4 systems at 25 °C is equal to:

  17. 17
    UHS MDCAT 2017

    For which of the following equilibrium reaction, Kc has no units:

  18. 18
    UHS MDCAT 2017

    Consider the following reversible reaction: Initial concentrations:

    CH3-CH2-OH) = 1 mol.dm-3(CH3-COOH)= 1 mol.dm-3(CH3-CH2-O-CO-CH3)= 0 mol.dm-3(H2O)= 0 mol.dm-3

    Equilibrium concentrations:(CH3-CH2-OH) = 0.33mol.dm-3(CH3-COOH)= 0.33 mol.dm-3(CH3-CH2-O-CO-CH3)= 0.66 mol.dm-3(H2O)= 0.66 mol.dm-3

    Kc= 4 at temperature 100

    What are the new equilibrium concentrations of all species if 1 mol.dm-3 of CH3-CH2-OH and CH3-COOH are added to this equilibrium mixture? (Apply Le-Chatelier’s principle)(Temperature and Kc remain constant)

  19. 19
    UHS MDCAT 2017 (Reconduct)

    Ca(OH)2 is sparingly soluble having solubility constant value 6.5 x 10-6. What’ll be its solubility:

  20. 20
    UHS MDCAT 2018

    According to Lowry - Bronsted Acid & Base Concept, H2O is:

  21. 21
    UHS MDCAT 2018

    The product of the concentrations of each ion in a saturated solution of a sparingly soluble salt at 298 K, raised to the power of their relative concentrations is:

  22. 22
    UHS MDCAT 2019

    For the following equilibrium reaction, when the forward reaction is exothermic; an increase in temperature shifts the equilibrium position towards the left. What will occur in that scenario? 2SO2 + O2 ⇌ 2SO3

  23. 23
    UHS MDCAT 2019

    The Ka values of HCI, CH3COOH, HF, and H2SO4 are 107, 1.85 x 10-5, 6.7 x 10-5 and 102 respectively. The decreasing order of acidic strength is:

  24. 24
    UHS MDCAT 2019

    The pH of 10-2 M aqueous solution of sodium hydroxide is:

  25. 25
    UHS MDCAT 2024

    Consider the following reaction in equilibrium and tell addition of which chemical will turn the cloudy solution into clear solution?

    BiCl3 + H2OBiOCl + 2HCl

  26. 26
    UHS MDCAT 2024

    The principle that states that if a stress is applied to a system at equilibrium, the system nullifies the effect of stress as far as possible is:

  27. 27
    PMDC MDCAT 2025

    What happens when H+ is added to ammonium hydroxide and ammonium chloride buffer?

  28. 28
    PMDC MDCAT 2025

    Which of the following is a basic buffer?

  29. 29

    In exothermic reaction, by decreasing the temperature, equilibrium constant:

  30. 30
    Select the buffer solution having highest pH:
  31. 31
    NUMS MDCAT 2024
    What conditions should be applied to minimize the leftover reactants in ammonia synthesis?
  32. 32
    The solubility of PbS at 25°C is 4.0 × 10⁻²⁸. Then ionic concentration will be:
  33. 33
    Suppose the following system has reached equilibrium at a certain temperature: N₂O₄(g) ⇌ 2NO₂(g). Adding N₂O₄ to the system will:
  34. 34
    The sum of pH and pOH for pure water at 25°C is:
  35. 35
    Equilibrium constant has no units, if the number of moles of product are:
  36. 36
    Le-Chatelier's principle does not give the information of effect of the following on equilibrium:
  37. 37
    Sindh MDCAT 2024
    A colloidal solution of liquid into liquid is known as:
  38. 38
    Sindh MDCAT 2024
    According to Raoult's law, the relative lowering of vapor pressure is equal to:
  39. 39
    Conjugated acid of NH₃ is:
  40. 40
    The term 'active mass' used in the Law of Mass Action means:
  41. 41
    Sindh MDCAT 2024
    The pH value of human blood is:
  42. 42
    The equilibrium of this reaction would not be affected by an increase in pressure:
  43. 43
    The unit of Kc for the system PCl₅ → PCl₃ + Cl₂ is:
  44. 44
    Consider N₂ + 3H₂(g) → 2NH₃(g) ΔH = -92.46 kJ/mol. The optimum temperature (°C) to produce ammonia is:
  45. 45
    In the production of SO₃ from SO₂ and Oxygen, the yield of SO₃ is increased by:
  46. 46
    Forward reaction is the one that:
  47. 47
    The pKa of n-propyl amine is:
  48. 48
    Which of the following factor will disturb chemical equilibrium in a given reaction? 2HI(g) ⇌ H₂(g) + I₂(g) ΔH° = +ive. 1. Change in concentration, 2. Change in temperature, 3. Change in pressure, 4. Change in volume
  49. 49
    FMDC MDCAT 2024 (Reconduct)
    Maximum yield of ammonia can be obtained by:
  50. 50
    If weak acid is diluted with water, then H⁺ ions concentration will ______.
  51. 51
    What will be the molarity of HCl solution with pH = 4?
  52. 52
    According to law of mass action, Kp > Kc when reaction occurs with ______.
  53. 53
    Which of the following mixture will constitute the buffer solution? (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂)
  54. 54
    Chemical equilibrium given below will shift to backward direction by ______. 2NO + O₂ ⇌ 2NO₂ + Heat
  55. 55
    In endothermic reaction, the heat content of the:
  56. 56
    Consider the following reaction in the equilibrium and tell addition of which will turn the cloudy solution into clear solution? BiCl₃ + H₂O ⇌ BiOCl + 2HCl
  57. 57
    Identify the correct option required for the maximum yield of ammonia in Haber's process:
  58. 58
    The principle that states if a stress is applied to a system at equilibrium the system will nullify the effect of stress as far as possible is:
  59. 59
    NUMS MDCAT 2023
    The high pressure of 200 atm in Haber's process is used for:
  60. 60
    Temperature increase in an exothermic reversible reaction, shift the equilibrium to:
  61. 61
    The equilibrium stage that is not affected by temperature is called?
  62. 62
    The solubility of KClO₃ is decreased by adding:
  63. 63
    Which of the following is true for reversible reaction at equilibrium?
  64. 64
    Which of the following conditions required for maximum yield of ammonia through Haber's process?
  65. 65
    Which of the following reactions has same value of Kc & Kp?
  66. 66
    For Δn = 0:
  67. 67
    If ionic product is less than Ksp then:
  68. 68
    Haber's process is used for the synthesis of ammonia. The optimum temperature for the Haber process is:
  69. 69
    For a gaseous phase reaction, when number of moles of reactant and product are equal:
  70. 70
    What is not true about the Le-Chatelier's principle?
  71. 71
    N₂ + 3H₂ ⇌ 2NH₃ (ΔH = -92.5). Which condition favours forward reaction?
  72. 72
    UHS MDCAT 2023
    In reversible reaction, when product is removed, the equilibrium shift towards the:
  73. 73
    UHS MDCAT 2023
    What is the ultimate fate of reversible reaction?
  74. 74
    NUMS MDCAT 2022
    Which term describes a solution in which dissolved solute is in equilibrium with undissolved solute?
  75. 75
    FMDC MDCAT 2024 (Reconduct)
    The pH of human blood is:
  76. 76
    UHS MDCAT 2023
    Acetic acid is weak acid than sulphuric acid because of which of the following reasons?
  77. 77
    Balochistan MDCAT 2022
    Why a reaction is reversible?
  78. 78
    The precipitation occurs, if the ionic concentration is:
  79. 79
    Sindh MDCAT 2022
    The solubility product Ksp predicts whether:
  80. 80
    At equilibrium in a reversible reaction:
  81. 81
    The value of solubility products depends only on ______.
  82. 82
    If solubility product (Ksp) value is large the salt in water is:
  83. 83
    Buffer capacity is maximum when both components have:
  84. 84
    Which of the following is not the use of the Buffer solution?
  85. 85
    FMDC MDCAT 2022
    By which of the following factors equilibrium state is attained earlier?
  86. 86
    The high pressure of 200 atm in Haber process is used for:
  87. 87
    For the chemical reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) + Heat. We can maximize the yield of NH₃:
  88. 88
    UHS MDCAT 2023 UHS MDCAT 2022
    One can estimate the direction in which equilibrium will shift with the help of:
  89. 89
    UHS MDCAT 2022 Balochistan MDCAT 2022
    The precipitation occurs if the ionic concentration is:
  90. 90
    UHS MDCAT 2022
    The decrease in solubility of the salt in a solution that already contains an ion common to that salt is known as:
  91. 91
    Manufacturing of Ammonia by Haber's process is an:
  92. 92
    PMC Practice Test 1 2021 PMC Practice Test 1 2022
    The equilibrium constant is always written as a ratio of:
  93. 93
    According to Le-Chatelier's principle, exothermic reactions are favored by:
  94. 94
    H₂ + I₂ ⇌ 2HI. Relation between Kp and Kc for this reaction is:
  95. 95
    PMDC MDCAT 2020
    Purification of table salt (NaCl) by passing HCl gas through its saturated aqueous solution is an example of:
  96. 96
    FMDC MDCAT 2023 PMDC MDCAT 2020
    For a gaseous phase reaction, when number of moles of reactants and products are equal:
  97. 97
    The equation N₂(g) + 3H₂(g) ⇌ 2NH₃(g) represents:
  98. 98
    Which of the following reaction has greater Kp than Kc (Kp > Kc)?
  99. 99
    For an equilibrium reaction: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g). The forward reaction is exothermic, increase in temperature shifts the equilibrium position towards left because:
  100. 100
    Ice and water is in equilibrium with each other. By increasing the pressure the equilibrium will shift in:
  101. 101
    Consider the reversible reaction: N₂ + 2NH₃ ⇌ 2NH₄ + Heat. The yield of NH₃ will be maximum at:
  102. 102
    pKa values of some acids are given below; choose the weaker acid?
  103. 103
    Kp = Kc(RT)ⁿ in the equation if Δn < 0 then:
  104. 104
    Precipitation occurs when the product of ionic concentration is?
  105. 105
    The pKa value of CH₃COOH is 4.74, the pH of equimolar solution of acetic acid and sodium acetate is:
  106. 106
    What is the pH of 0.1M of HCl?
  107. 107
    Which one of the following bases has highest Kb value?
  108. 108
    The Kc Unit for the reaction N₂(g) + 3H₂(g) → 2NH₃(g) is:
  109. 109
    Which one of the following factors does not affect the equilibrium position?
  110. 110
    Which of the following factors affect a reversible chemical reaction in accordance with the Le-Chatelier's principle?
  111. 111
    The product of the concentrations of each ion in saturated solution of a sparingly soluble salt at 298K raised to the power of their relative concentrations is:
  112. 112
    Ca(OH)₂ is sparingly soluble having solubility product value 6.5 × 10⁻⁶. What will be its solubility?
  113. 113
    Consider the following reversible reaction: CH₃CH₂OH + CH₃COOH ⇌ CH₃CH₂OOCCH₃ + H₂O. Initial concentration: (CH₃CH₂OH) = 1mol, (CH₃COOH) = 1mol, ester = 0mol, H₂O = 0mol. Equilibrium concentration: (CH₃CH₂OH) = 0.333mol, (CH₃COOH) = 0.333mol, ester = 0.666mol, H₂O = 0.666mol. Kc = 4 at 100°C. What are new equilibrium concentrations of all species if 1 mole of each of CH₃CH₂OH and CH₃COOH are added to this equilibrium mixture? (Apply Le-Chatelier's Principle, Temperature remained same)
  114. 114
    For which of the following equilibrium reaction, Kc has no units?
  115. 115
    Value of Ksp for PbSO₄ system at 25°C is equal to:
  116. 116
    UHS MDCAT 2016
    Human blood maintains its pH between:
  117. 117
    Which one of the following is the correct representation for Ksp? AgCl ⇌ Ag⁺ + Cl⁻
  118. 118
    UHS MDCAT 2015
    What is the correct relation between pH and pKa?
  119. 119
    During the manufacture of nitric acid, nitric oxide is oxidized to nitrogen dioxide. This reaction is given as: 2NO(g) + O₂(g) ⇌ 2NO₂(g) ΔH = -114 kJ/mol. According to Le Chatelier's Principle:
  120. 120
    What will be the pH of a solution of NaOH with a concentration of 10⁻³ M?
  121. 121
    The value of equilibrium constant Kc for the reaction 2HF(g) ⇌ H₂(g) + F₂(g) is 10⁻¹³ at 2000°C. Calculate the value of Kp for this reaction.
  122. 122
    The 'pH' of our blood is:
  123. 123
    The chemical substance, when dissolved in water, gives 'H⁺' is called:
  124. 124
    A buffer solution is that which resists/minimizes the change in
  125. 125
    Formation of NH₃ is reversible and exothermic process, what will happen on cooling?
  126. 126
    If in AgCl solution, some salt of NaCl is added, AgCl will be precipitated due to:
  127. 127
    Units of Kc for the following reaction is: H₂ + I₂ → 2HI
  128. 128
    In a saturated solution of AgCl, the molar concentration of Ag⁺ and Cl⁻ is 1.0×10⁻⁵M each. What is the value of Ksp?
  129. 129
    The solubility product is only applicable for those substances whose molar concentrations is:
  130. 130

    If ionic product is equal to Ksp then the solution is:

  131. 131
    Ionization of KClO₃ is suppressed by:
  132. 132
    An excess of silver nitrate is added to the aqueous barium chloride and the precipitate is removed by filtration. What are the main ions in the filtrate?
  133. 133
    When HCl gas is passed through saturated solution of rock salt, the solubility of NaCl:
  134. 134
    For acidic buffer, pH < pKa if:
  135. 135
    A certain buffer solution contains equal concentration of X⁻ and HX. Ka for HX is 10⁻¹¹. The pH of buffer is:
  136. 136
    The pH of ideal buffer is:
  137. 137
    A basic buffer solution can be prepared by mixing:
  138. 138
    Buffer action can be explained by all except:
  139. 139
    Basic buffer solution is:
  140. 140
    Catalyst used in Haber's process for manufacturing of NH₃ is:
  141. 141
    In Haber process, equilibrium mixture contains NH₃ by volume:
  142. 142
    If the temperature is increased for the following reaction, then it will go in: N₂ + 3H₂ ⇌ 2NH₃, ΔH = -ve
  143. 143
    In a given system, water and ice are in equilibrium. If pressure is applied to the system then?
  144. 144
    N₂ + 3H₂ ⇌ 2NH₃, ΔH = -41.02 kJ/mol. Forward reaction is favoured by:
  145. 145
    In the reaction A₂(g) + 4B₂(g) ⇌ 2AB₄(g) such that ΔH is negative, the formation of AB₄(g) will be favoured at:
  146. 146
    For the following reaction in the gaseous phase: CO + ½O₂ ⇌ CO₂, Kp/Kc equals:
  147. 147
    For the reaction H₂ + I₂ ⇌ 2HI, equilibrium concentration of H₂, I₂ and HI are 8, 3 and 24 mol/dm³ respectively. Kc of the reaction is:
  148. 148
    For the given reaction PCl₅ ⇌ PCl₃ + Cl₂:
  149. 149
    For the reaction H₂ + I₂ ⇌ 2HI(g), the equilibrium constant changes with:
  150. 150
    For the reaction with equilibrium expression Kc = [products]/[reactants], what is true?
  151. 151
    If Kc value is very small then equilibrium position will shift:
  152. 152

    In a reaction CO(g) + 2H2(g) CH3OH(g) H= -92kJ/mol where concentration of hydrogen, carbon monoxide and methanol become constant at equilibrium, what will happen?

  153. 153
    At equilibrium, concentration of SO₂ is 2M, O₂ is 2M and SO₃ is 4M. For the reaction 2SO₂ + O₂ ⇌ 2SO₃, what will be the Kc value?
  154. 154
    1 mole of ethyl alcohol was treated with one mole of acetic acid at 25°C. 2/3rd of acid changes into ester at equilibrium. The equilibrium constant of the reaction will be:
  155. 155
    For what value of Kc is the forward reaction almost completed?
  156. 156
    One mole of HI was sealed in a tube heated at 440°C till equilibrium is reached. HI was found to be 50% dissociated. Kc for the reaction is:
  157. 157
    For a homogeneous reaction 4NH₃ + 5O₂ ⇌ 4NO + 6H₂O, the units of equilibrium constant are:
  158. 158
    Which statement describes a reversible reaction?
  159. 159
    At equilibrium, the concentration of reactants and products are:
  160. 160
    The addition of NaCl in AgCl solution decreases its solubility because
  161. 161
    N₂ + 3H₂ ⇌ 2NH₃: Then which statement is correct about this reaction?
  162. 162
    The solubility of AgI in NaI solution is less than that in pure water because
  163. 163
    The statement that is false about Kc is
  164. 164
    Haber's process operates at 450°C, if it is carried out at 200°C then
  165. 165

    Kc values of decomposition are given, suggest which oxide of nitrogen is most stable

  166. 166
    When the value of Kc of reaction is very small, it shows that
  167. 167
    When no of moles of reactant are greater than no of moles of product, then Kp has value:
  168. 168
    The chemical reaction in which product formed are non-reactive then the reactants is
  169. 169

    For this reaction N2(g) + O2(g) ⇌ 2NO(g), the relation between Kp and Kc is