Chemistry Chapter 6 Entry Test MCQs
76. Given that pKa of acetic acid is 4.7, what is pH of solution of 0.01 M acetic acid and 0.1 sodium acetate is:
a. 5.7
b. 3.7
c. 2.7
d. 4.7
77. Oxidation of SO2 by O2 is exothermic reaction. The yield of SO3 will be maximum if
a. Temperature is increased, pressure is kept constant
b. Temperature is reduced and pressure is increased
c. Both temperature and pressure are increased
d. Both temperature and pressure are decreased
78. Which is incorrect about common ion effect
a. Always in reverse direction
b. Best application of Le-Chatlier’s principle
c. Increase in solubility of weak electrolyte
d. It is the effect of increase in concentration of product in form of common ion
79. To prepare a buffer with pH close to 9.0, you could use a mixture of:
a. HNO2+NaNO2
b. NH4OH+NH4Cl
c. CH3COOH+CH3COONa
d. NaHCO3+H2CO3
80. For a reaction CO + H2O ⇌ CO2 + H2 at given temperature, the equilibrium amount of CO2 can be increased by:
a. Decreasing the volume of container
b. Adding suitable catalyst
c. Increasing the amount of CO
d. Adding an inert gas
81. When NaNO3 is heated in a closed vessel, the oxygen is liberated and NaNO2 left behind. At equilibrium:
a. Addition of NaNO2 favours forward reaction
b. Decreasing the temperature favours forward reaction
c. Removal of NaNO3 favours forward reaction
d. Increasing the temperature favours forward reaction
82. Which of the following factors will not favour the formation of SO3 according to the reaction? (2SO2 + O2 ⇌ 2SO3 + x Cal )
a. Decrease the concentration of reactants
b. At high pressure
c. At low temperature
d. Excess of oxygen or SO2
83. For reaction C(s) + CO2(g) ⇌ 2CO(g), the partial pressure of CO2 and CO are 2.0 and 4.0 atm respectively at equilibrium. The KP of reaction is:
a. 4
b. 0.5
c. 8
d. 32
84. In what manner will increase of pressure affect the following equation? CO (g) + H2O (g) ⇌ CO2 (g) + H2(g)
a. Shift in the forward direction
b. Shift in the reverse direction
c. No effect
d. Increase in the yield of hydrogen
85. The raw material, H2 in Haber’s process is obtained:
a. Methane
b. Air
c. Alcohol
d. Water
86. Which of the following change will decrease the amount of steam?
2H2O(g) ⇌ 2H2(g) + O2(g) ΔH = 241.7K
a. Increase the pressure at constant temperature
b. Addition of Pt catalyst
c. Increasing the temperature at constant
d. Addition of more oxygen
87. Yield of ammonia in Haber’s process can be increased by all except:
a. Adding nitrogen
b. Catalyst
c. Decreasing temperature
d. Increasing pressure
88. Increase in temperature the equilibrium reaction:
a. Variable average molecular speed
b. Alters the Kc
c. Changes the Kp
d. All of these
89. Which of the following can disrupt the equilibrium of a reversible reaction, most drastically?
a. Changing the temperature
b. Adding a catalyst
c. Changing the volume
d. Changing the pressure
90. A catalyst when added to a reaction at equilibrium will
a. Increases forward reaction rate
b. Increases reverse reaction rate
c. Decrease activation energy
d. All of these
91. In an exothermic reaction, increasing the temperature will cause the equilibrium to shift:
a. Towards the reactants
b. Towards the products
c. Equilibrium is not affected by temperature changes
d. In the opposite direction of the reaction
92. What happens when a catalyst is added to a reaction mixture at equilibrium?
a. Reactions become irreversible
b. Reactions become unidirectional
c. Concentration changes
d. The rate constant changes
93. Higher density of water than ice ensures that when pressure is applied to the equilibrium system Ice ⇌ water?
a. System absorbs heat
b. System releases heat
c. More ice is formed
d. More water is formed
94. In an exothermic reaction, formation of reactants is favoured by:
a. Addition of cooling agent
b. Low P
c. Heating
d. Low V
95. KClO3 is:
a. A salt of KCl with weak base
b. An acid
c. A salt of KOH with strong acid
d. A buffer
96. For an exothermic reaction which proceeds with increase in number of moles, the amount of product obtained depends upon:
a. Temperature and Pressure
b. Temperature alone
c. Temperature, Pressure and Catalyst
d. Pressure alone
97. In Haber process, equilibrium mixture contains 35% NH3 by volume, it means value of Kc is:
a. =1
b. >1
c. <1
d. >2
98. When a small amount of an acid or a base is added to a buffer solution, its pH value will change:
a. Rapidly
b. Drastically
c. A little
d. Not at all
99. The equilibrium of a reversible reaction is disturbed by:
a. Shaking the reaction container
b. The addition of a catalyst
c. Heating the reaction mixture
d. All of the above
100. Which of the following best explains buffer action?
a. Common ion effect
b. Equilibrium constant
c. Ionic product
d. Solubility Product