Equilibrium CBSE Questions & Answers

Equilibrium

This is Chemistry Class 11 Equilibrium CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
At 500 K, equilibrium constant, \({{\text{K}}_{\text{c}}}\), for the following reaction is 5.2. \(\frac{1}{2}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right) + \frac{1}{2}{\text{ }}{{\text{I}}_{\text{2}}}\left( {\text{g}} \right) \rightleftharpoons \) HI (g) What would be the equilibrium constant Kc for the reaction 2HI (g) \( \rightleftharpoons \) \({{\text{H}}_{\text{2}}}\left( {\text{g}} \right){\text{ }} + {{\text{I}}_{\text{2}}}\left( {\text{g}} \right)\)
  • A
    0.4
  • B
    25
  • C
    2.5
  • D
    0.04
    Correct
2
In which of the following reactions, the equilibrium remains unaffected on addition of small amount of argon at constant volume?
  • A
    \({{\text{H}}_{\text{2}}}\left( {\text{g}} \right){\text{ }} + {\text{ }}{{\text{I}}_{\text{2}}}\left( {\text{g}} \right)\) \( \rightleftharpoons \) 2HI (g)
    Correct
  • B
    \({{\text{N}}_{\text{2}}}\left( {\text{g}} \right){\text{ }} + {\text{ 3}}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right) \rightleftharpoons {\text{2N}}{{\text{H}}_{\text{3}}}\left( {\text{g}} \right)\)
  • C
    \({\text{PC}}{{\text{l}}_{\text{5}}}\left( {\text{g}} \right)\) \( \rightleftharpoons \) \({\text{PC}}{{\text{l}}_{\text{3}}}\left( {\text{g}} \right){\text{ }} + {\text{ C}}{{\text{l}}_{\text{2}}}\left( {\text{g}} \right)\)
  • D
    The equilibrium will remain unaffected in all the three cases.
3
For the reaction \({{\text{N}}_{\text{2}}}{{\text{O}}_{\text{4}}}\left( {\text{g}} \right)\) \( \rightleftharpoons \)\({\text{2N}}{{\text{O}}_{\text{2}}}\left( {\text{g}} \right)\), the value of K is 50 at 400 K and 1700 at 500 K. Which of the following option is incorrect?
  • A
    If \({\text{N}}{{\text{O}}_{\text{2}}}\) (g) and \({{\text{N}}_{\text{2}}}{{\text{O}}_{\text{4}}}\) (g) are mixed at 400 K at partial pressures 20 bar and 2 bar respectively, more \({{\text{N}}_{\text{2}}}{{\text{O}}_{\text{4}}}\) (g) will be formed
  • B
    The entropy of the system increases
  • C
    The reaction is endoothermic
  • D
    The reaction is exothermic
    Correct
4
At a particular temperature and atmospheric pressure, the solid and liquid phases of a pure substance can exist in equilibrium. Which of the following term defines this temperature?
  • A
    Boiling point
  • B
    Phase change temperature
  • C
    Equilibrium temperature
  • D
    Normal melting point and Freezing point
    Correct
5
The ionisation of hydrochloric in water is given below:\({\text{HCl }}\left( {{\text{aq}}} \right){\text{ }} + {\text{ }}{{\text{H}}_{\text{2}}}{\text{O }}\left( {\text{l}} \right)\) \( \rightleftharpoons \) \(H3O + (aq) + C{l^ - }(aq)\)
  • A
    \(HClC{l^ - }\)
    Correct
  • B
    \(H2OC{l^ - }\)
  • C
    \({\text{HCl }}{{\text{H}}_{\text{3}}}{\text{O}} + \)
  • D
    \(H3O + C{l^ - }\)
6
The aqueous solution of sugar does not conduct electricity. However, when sodium chloride is added to water, it conducts electricity. How will you explain this statement on the basis of ionisation and how is it affected by concentration of sodium chloride?
  • A
    NaCl ionises completely in water and increase in concentration of salt increases conductance.
    Correct
  • B
    Sugar releases more ions in water and increases conductance
  • C
    Both sugar and NaCl ionises completely in water thereby increasing the conductance
  • D
    Both sugar and NaCl ionises partially in water thereby increasing the conductance
7
\({\text{B}}{{\text{F}}_{\text{3}}}\)does not have proton but still acts as an acid and reacts with NH3. Why is it so? What type of bond is formed between the two?
  • A
    \({\text{B}}{{\text{F}}_{\text{3}}}\) is a Brönsted acid and coordinate bond is formed
  • B
    \({\text{B}}{{\text{F}}_{\text{3}}}\) is a Lewis acid and coordinate bond is formed
    Correct
  • C
    \({\text{B}}{{\text{F}}_{\text{3}}}\) is a Lewis acid and coordinate bond is formed
  • D
    \({\text{B}}{{\text{F}}_{\text{3}}}\) is a Brönsted acid and coordinate bond is formed
8
\(0.{\text{3 g of Ca}}{\left( {{\text{OH}}} \right)_{\text{2}}}\) is dissolved in water to give 500 mL of solution. The pH of the solution is
  • A
    11.053
  • B
    12.098
    Correct
  • C
    10.099
  • D
    14.027
9
Calculate the hydrogen ion concentration in the human blood whose pH is 7.38.
  • A
    \(6.33x?10{?^{( - 8)}}M\)
  • B
    \(3.19x?10{?^{( - 8)}}M\)
  • C
    \(4.17x?10{?^{( - 8)}}M\)
    Correct
  • D
    \(5.16x?10{?^{( - 8)}}M\)
10
The ionization constant of acetic acid is\({\text{1}}.{\text{74 x 1}}{0^{ - {\text{5}}}}\). . Calculate the degree of dissociation of acetic acid in its 0.05 M solution. Calculate the concentration of acetate ion in the solution and its pH.
  • A
    0.00193M and pH 3.03
  • B
    0.00203M and pH 3.03
  • C
    0.00093M and pH 3.03
    Correct
  • D
    0.00013M and pH 3.03
11
It has been found that the pH of a 0.01M solution of an organic acid is 4.15.Calculate the concentration of the anion, the ionization constant of the acid and its \({\text{p}}{{\text{K}}_{\text{a}}}\)
  • A
    \({{\text{K}}_{\text{a}}} = {\text{5}}.0{\text{1 X}}\) \({10^{ - 7}}\) , \(\left[ {{{\text{A}}^ - }} \right]\) \( = {\text{7}}.0{\text{8 X}}\) \({10^{ - 5}}\) and \({\text{p}}{{\text{K}}_{\text{a}}} = {\text{ 5}}.{\text{3}}00{\text{7}}\)
  • B
    \({{\text{K}}_{\text{a}}} = {\text{5}}.0{\text{1 X}}\) \({10^{ - 7}}\) , \(\left[ {{{\text{A}}^ - }} \right]\) \( = {\text{7}}.{\text{39 X}}\) \({10^{ - 5}}\) and \({\text{p}}{{\text{K}}_{\text{a}}} = {\text{ 6}}.{\text{3}}00{\text{1}}\)
  • C
    \({{\text{K}}_{\text{a}}} = {\text{5}}.0{\text{1 X}}\) \({10^{ - 7}}\) , \(\left[ {{{\text{A}}^ - }} \right]\) \( = {\text{7}}.{\text{99 X}}\) \({10^{ - 5}}\) and \({\text{p}}{{\text{K}}_{\text{a}}} = {\text{ 7}}.{\text{5}}00{\text{9}}\)
  • D
    \({{\text{K}}_{\text{a}}} = {\text{5}}.0{\text{1 X}}\) \({10^{ - 7}}\) , \(\left[ {{{\text{A}}^ - }} \right]\) \( = {\text{7}}.0{\text{8 X}}\) \({10^{ - 5}}\) and \({\text{p}}{{\text{K}}_{\text{a}}} = {\text{ 6}}.{\text{3}}00{\text{1}}\)
    Correct
12
If, in the reaction \({{\text{N}}_{\text{2}}}{{\text{O}}_{\text{4}}}\)\( \rightleftharpoons \)\({\text{2N}}{{\text{O}}_{\text{2}}},{\text{ x}}\) is that part of \({{\text{N}}_{\text{2}}}{{\text{O}}_{\text{4}}}\)which dissociates, then the number of molecules at equilibrium will be
  • A
    1 + x)
    Correct
  • B
    1
  • C
    \({\left( {{\text{1 }} + {\text{ xy}}} \right)^{\text{2}}}\)
  • D
    3
13
The \({\text{Ksp}}\) for \({\text{Cr}}{\left( {{\text{OH}}} \right)_{\text{3}}}{\text{is 1}}.{\text{6 }} \times {\text{ 1}}{0^{--{\text{3}}0}}\). The molar solubility of this compound in water is :
  • A
    \({\text{1}}.{\text{6 }} \times {\text{ 1}}{0^{--{\text{3}}0}}/{\text{27}}\)
  • B
    \(\sqrt[2]{{1.6 \times {{10}^{ - 30}}}}\)
  • C
    \(\sqrt[4]{{1.6 \times {{10}^{ - 30}}}}\)
  • D
    \(\sqrt[4]{{1.6 \times {{10}^{ - 30}}/27}}\)
    Correct
14
pH of a saturated solution of \({\text{Ba}}{\left( {{\text{OH}}} \right)_{\text{2}}}\) is 12. The value of solubility product \(\left( {{{\text{K}}_{{\text{sp}}}}} \right){\text{ of Ba}}{\left( {{\text{OH}}} \right)_{\text{2}}}\) is
  • A
    \({\text{3}}.{\text{3 }} \times {\text{ 1}}{0^{--{\text{7}}}}\)
  • B
    \({\text{5}}.0{\text{ }} \times {\text{ 1}}{0^{--{\text{7}}}}\)
    Correct
  • C
    \({\text{5}}.0{\text{ }} \times {\text{ 1}}{0^{--{\text{6}}}}\)
  • D
    \({\text{4}}.0{\text{ }} \times {\text{ 1}}{0^{--{\text{6}}}}\)
15
The solubility of \({\text{C}}{{\text{a}}_{\text{3}}}{\left( {{\text{P}}{{\text{O}}_{\text{4}}}} \right)_{\text{2}}}\) in water is y moles/litre. Its solubility product is
  • A
    \({\text{1}}0{\text{8}}{{\text{y}}^{\text{5}}}\)
    Correct
  • B
    \({\text{6}}{{\text{y}}^{\text{4}}}\)
  • C
    \({\text{64}}{{\text{y}}^{\text{5}}}\)
  • D
    \({\text{36}}{{\text{y}}^{\text{4}}}\)