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Class 10 Chemistry Chemical Equilibrium What is the importance of equilibrium constant?


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What is the importance of equilibrium constant?

Q14 In the equilibrium\[\mathrm{PCl}_{5}(\mathrm{~g}) \square \mathrm{PCl}_{3}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g}) \Delta \mathrm{H}=+90 \mathrm{~kJ} \mathrm{~mol}^{-1}\]What is the effect on(a) the position of equilibrium(b) equilibrium constant? ifi) temperature is increased
Q14 In the equilibrium\[\mathrm{PCl}_{5}(\mathrm{~g}) \square  \mathrm{PCl}_{3}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g})  \Delta \mathrm{H}=+90 \mathrm{~kJ} \mathrm{~mol}^{-1}\]What is the effect on(a) the position of equilibrium(b) equilibrium constant? ifi) temperature is increased

Q14 In the equilibrium\[\mathrm{PCl}_{5}(\mathrm{~g}) \square \mathrm{PCl}_{3}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g}) \Delta \mathrm{H}=+90 \mathrm{~kJ} \mathrm{~mol}^{-1}\]What is the effect on(a) the position of equilibrium(b) equilibrium constant? ifi) temperature is increased

Q8 (a) Write down \mathrm{K}_{c} for the following reversible reactions. Suppose that the volume of reaction mixture in all the cases is V^{\prime \prime} \mathrm{dm}^{3} at equilibrium stage.V) \mathrm{N}_{2}+3 \mathrm{H}_{2} \square 2 \mathrm{NH}_{3}
Q8 (a) Write down  \mathrm{K}_{c}  for the following reversible reactions. Suppose that the volume of reaction mixture in all the cases is  V^{\prime \prime} \mathrm{dm}^{3}  at equilibrium stage.V)   \mathrm{N}_{2}+3 \mathrm{H}_{2} \square  2 \mathrm{NH}_{3}

Q8 (a) Write down \mathrm{K}_{c} for the following reversible reactions. Suppose that the volume of reaction mixture in all the cases is V^{\prime \prime} \mathrm{dm}^{3} at equilibrium stage.V) \mathrm{N}_{2}+3 \mathrm{H}_{2} \square 2 \mathrm{NH}_{3}

ii) Which statement about the following equilibrium is correct 2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \square 2 \mathrm{SO}_{3}(\mathrm{~g}) \ddot{A} \mathrm{H}=-188.3 \mathrm{~kJ} \mathrm{~mol}{ }^{-1} (a) The value of K_{p} falls with a rise in temperature(b) The value of K_{p} falls with increasing pressure(c) Adding \mathrm{V}_{2} \mathrm{O}_{5} catalyst increase the equilibrium yield of sulphur trioxide(d) The value of K_{0} is equal to K_{\text {c. }} .
ii) Which statement about the following equilibrium is correct  2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \square 2 \mathrm{SO}_{3}(\mathrm{~g})   \ddot{A} \mathrm{H}=-188.3 \mathrm{~kJ} \mathrm{~mol}{ }^{-1} (a) The value of  K_{p}  falls with a rise in temperature(b) The value of  K_{p}  falls with increasing pressure(c) Adding  \mathrm{V}_{2} \mathrm{O}_{5}  catalyst increase the equilibrium yield of sulphur trioxide(d) The value of  K_{0}  is equal to  K_{\text {c. }} .

ii) Which statement about the following equilibrium is correct 2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \square 2 \mathrm{SO}_{3}(\mathrm{~g}) \ddot{A} \mathrm{H}=-188.3 \mathrm{~kJ} \mathrm{~mol}{ }^{-1} (a) The value of K_{p} falls with a rise in temperature(b) The value of K_{p} falls with increasing pressure(c) Adding \mathrm{V}_{2} \mathrm{O}_{5} catalyst increase the equilibrium yield of sulphur trioxide(d) The value of K_{0} is equal to K_{\text {c. }} .

Example:Calculate the \mathrm{pH} of a buffer solution in which 0.11 molar \mathrm{CH}_{3} \mathrm{COONa} and 0.09 molar acetic acid solutions are present. \mathrm{K}_{\mathrm{a}} for \mathrm{CH}_{3} \mathrm{COOH} is 1.85 \times 10^{-5}
Example:Calculate the  \mathrm{pH}  of a buffer solution in which  0.11  molar  \mathrm{CH}_{3} \mathrm{COONa}  and  0.09  molar acetic acid solutions are present.  \mathrm{K}_{\mathrm{a}}  for  \mathrm{CH}_{3} \mathrm{COOH}  is  1.85 \times 10^{-5}

Example:Calculate the \mathrm{pH} of a buffer solution in which 0.11 molar \mathrm{CH}_{3} \mathrm{COONa} and 0.09 molar acetic acid solutions are present. \mathrm{K}_{\mathrm{a}} for \mathrm{CH}_{3} \mathrm{COOH} is 1.85 \times 10^{-5}

1. For the decomposition of dinitrogen oxide \left(\mathrm{N}_{2} \mathrm{O}\right) into nitrogen and oxygen reversible reaction takes place as follows\[2 \mathrm{~N}_{2} \mathrm{O}_{(\mathrm{g})} \rightleftharpoons 2 \mathrm{~N}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})}\]The concentration of \mathrm{N}_{2} \mathrm{O} \mathrm{N}_{2} and \mathrm{O}_{2} are 1.1 \mathrm{~mol} \mathrm{dm}^{-3} 3.90 \mathrm{~mol} \mathrm{dm}^{-3} and 1.95 \mathrm{~mol} \mathrm{dm}^{-3} respectively at equilibrium. Find out \mathrm{K}_{\mathrm{c}} for this reaction.
1. For the decomposition of dinitrogen oxide  \left(\mathrm{N}_{2} \mathrm{O}\right)  into nitrogen and oxygen reversible reaction takes place as follows\[2 \mathrm{~N}_{2} \mathrm{O}_{(\mathrm{g})} \rightleftharpoons 2 \mathrm{~N}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})}\]The concentration of  \mathrm{N}_{2} \mathrm{O} \mathrm{N}_{2}  and  \mathrm{O}_{2}  are  1.1 \mathrm{~mol} \mathrm{dm}^{-3} 3.90 \mathrm{~mol} \mathrm{dm}^{-3}  and  1.95 \mathrm{~mol} \mathrm{dm}^{-3}  respectively at equilibrium. Find out  \mathrm{K}_{\mathrm{c}}  for this reaction.

1. For the decomposition of dinitrogen oxide \left(\mathrm{N}_{2} \mathrm{O}\right) into nitrogen and oxygen reversible reaction takes place as follows\[2 \mathrm{~N}_{2} \mathrm{O}_{(\mathrm{g})} \rightleftharpoons 2 \mathrm{~N}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})}\]The concentration of \mathrm{N}_{2} \mathrm{O} \mathrm{N}_{2} and \mathrm{O}_{2} are 1.1 \mathrm{~mol} \mathrm{dm}^{-3} 3.90 \mathrm{~mol} \mathrm{dm}^{-3} and 1.95 \mathrm{~mol} \mathrm{dm}^{-3} respectively at equilibrium. Find out \mathrm{K}_{\mathrm{c}} for this reaction.

11. Write note on :(ii) dynamic equilibrium
11. Write note on :(ii) dynamic equilibrium

11. Write note on :(ii) dynamic equilibrium

2. Hydrogen iodide decomposes to form hydrogen and iodine. If the equilibrium concentration of \mathrm{HI} is 0.078 \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{H}_{2} and \mathrm{I}_{2} is same 0.011 \mathrm{~mol} \mathrm{dm}^{-3} . Calculate the equilibrium constant value for this reversible reaction:
2. Hydrogen iodide decomposes to form hydrogen and iodine. If the equilibrium concentration of  \mathrm{HI}  is  0.078 \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{H}_{2}  and  \mathrm{I}_{2}  is same  0.011 \mathrm{~mol} \mathrm{dm}^{-3} . Calculate the equilibrium constant value for this reversible reaction:

2. Hydrogen iodide decomposes to form hydrogen and iodine. If the equilibrium concentration of \mathrm{HI} is 0.078 \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{H}_{2} and \mathrm{I}_{2} is same 0.011 \mathrm{~mol} \mathrm{dm}^{-3} . Calculate the equilibrium constant value for this reversible reaction:

7. Consider the following equilibria:(i) 3 \mathrm{O}_{2(s)} \rightleftharpoons 2 \mathrm{O}_{3(s)} \Delta \mathrm{H}= positive(ii) \mathrm{H}_{2(s)}+\mathrm{I}_{2(s)} 2 \mathrm{HI}_{(\omega)} \Delta \mathrm{H}= positive(iii) 2 \mathrm{SO}_{2(3)} \cdot \mathrm{O}_{2(8)} \rightleftharpoons 2 \mathrm{SO}_{3(s)} \Delta \mathrm{H}= negative(b) In which direction will eachequilibrium change as the temperature is raised?
7. Consider the following equilibria:(i)  3 \mathrm{O}_{2(s)} \rightleftharpoons 2 \mathrm{O}_{3(s)}  \Delta \mathrm{H}=  positive(ii)  \mathrm{H}_{2(s)}+\mathrm{I}_{2(s)} 2 \mathrm{HI}_{(\omega)} \Delta \mathrm{H}=  positive(iii)  2 \mathrm{SO}_{2(3)} \cdot \mathrm{O}_{2(8)} \rightleftharpoons 2 \mathrm{SO}_{3(s)}  \Delta \mathrm{H}=  negative(b) In which direction will eachequilibrium change as the temperature is raised?

7. Consider the following equilibria:(i) 3 \mathrm{O}_{2(s)} \rightleftharpoons 2 \mathrm{O}_{3(s)} \Delta \mathrm{H}= positive(ii) \mathrm{H}_{2(s)}+\mathrm{I}_{2(s)} 2 \mathrm{HI}_{(\omega)} \Delta \mathrm{H}= positive(iii) 2 \mathrm{SO}_{2(3)} \cdot \mathrm{O}_{2(8)} \rightleftharpoons 2 \mathrm{SO}_{3(s)} \Delta \mathrm{H}= negative(b) In which direction will eachequilibrium change as the temperature is raised?

Q17 (a) What are buffer solutions? Why do we need them in daily life?
Q17 (a) What are buffer solutions? Why do we need them in daily life?

Q17 (a) What are buffer solutions? Why do we need them in daily life?

13. If reaction quotient Q_{c} of a reaction is more than K_{c} what will be the direction of the reaction?
13. If reaction quotient  Q_{c}  of a reaction is more than  K_{c}  what will be the direction of the reaction?

13. If reaction quotient Q_{c} of a reaction is more than K_{c} what will be the direction of the reaction?

11. Write note on :(iii) K_{C} and K_{p^{*}}
11. Write note on :(iii)  K_{C}  and  K_{p^{*}}

11. Write note on :(iii) K_{C} and K_{p^{*}}

Q15. Synthesis of ammonia by Habers process is an exothermic reaction.\[\mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \square 2 \mathrm{NH}_{3}(\mathrm{~g}) \ddot{A} H=-92.46 \mathrm{~kJ}\](d) What happens to equilibrium position of this reaction if \mathrm{NH}_{3} is removed from the reaction vessel from time to time?
Q15. Synthesis of ammonia by Habers process is an exothermic reaction.\[\mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \square  2 \mathrm{NH}_{3}(\mathrm{~g})   \ddot{A} H=-92.46 \mathrm{~kJ}\](d) What happens to equilibrium position of this reaction if  \mathrm{NH}_{3}  is removed from the reaction vessel from time to time?

Q15. Synthesis of ammonia by Habers process is an exothermic reaction.\[\mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \square 2 \mathrm{NH}_{3}(\mathrm{~g}) \ddot{A} H=-92.46 \mathrm{~kJ}\](d) What happens to equilibrium position of this reaction if \mathrm{NH}_{3} is removed from the reaction vessel from time to time?

10. State Le-Chateliers principle. What are its industrial applications?
10. State Le-Chateliers principle. What are its industrial applications?

10. State Le-Chateliers principle. What are its industrial applications?

Example 2: \mathrm{N}_{2}(\mathrm{~g}) and \mathrm{H}_{2} (g) combine to give \mathrm{NH}_{3}(\mathrm{~g}) . The value of \mathrm{K}_{\mathrm{c}} in this reaction at 500{ }^{\circ} \mathrm{C} is 6.0 \times 10^{-2} . Calculate the value of \mathrm{K}_{\mathrm{p}} for this reaction.
Example 2: \mathrm{N}_{2}(\mathrm{~g})  and  \mathrm{H}_{2}  (g) combine to give  \mathrm{NH}_{3}(\mathrm{~g}) . The value of  \mathrm{K}_{\mathrm{c}}  in this reaction at  500{ }^{\circ} \mathrm{C}  is  6.0 \times 10^{-2} .  Calculate the value of  \mathrm{K}_{\mathrm{p}}  for this reaction.

Example 2: \mathrm{N}_{2}(\mathrm{~g}) and \mathrm{H}_{2} (g) combine to give \mathrm{NH}_{3}(\mathrm{~g}) . The value of \mathrm{K}_{\mathrm{c}} in this reaction at 500{ }^{\circ} \mathrm{C} is 6.0 \times 10^{-2} . Calculate the value of \mathrm{K}_{\mathrm{p}} for this reaction.

What is the importance of equilibrium constant?
What is the importance of equilibrium constant?
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What is the importance of equilibrium constant?

v) An excess of aqueous silver nitrate is added to aqueous barium chloride and precipitate is removed by filtration. What are the main ions in the filtrate?(a) \mathrm{Ag}^{+} and \mathrm{NO}_{3} only(b) \mathrm{Ag}^{+} and \mathrm{Ba}^{2+} and \mathrm{NO}_{3} -(c) \mathrm{Ba}^{2+} and \mathrm{NO}_{3} only(d) \mathrm{Ba}^{2+} and \mathrm{NO}_{3} and \mathrm{Cl}^{-}
v) An excess of aqueous silver nitrate is added to aqueous barium chloride and precipitate is removed by filtration. What are the main ions in the filtrate?(a)  \mathrm{Ag}^{+} and  \mathrm{NO}_{3}  only(b)  \mathrm{Ag}^{+} and  \mathrm{Ba}^{2+}  and  \mathrm{NO}_{3}  -(c)  \mathrm{Ba}^{2+}  and  \mathrm{NO}_{3}  only(d)  \mathrm{Ba}^{2+}  and  \mathrm{NO}_{3}  and  \mathrm{Cl}^{-}

v) An excess of aqueous silver nitrate is added to aqueous barium chloride and precipitate is removed by filtration. What are the main ions in the filtrate?(a) \mathrm{Ag}^{+} and \mathrm{NO}_{3} only(b) \mathrm{Ag}^{+} and \mathrm{Ba}^{2+} and \mathrm{NO}_{3} -(c) \mathrm{Ba}^{2+} and \mathrm{NO}_{3} only(d) \mathrm{Ba}^{2+} and \mathrm{NO}_{3} and \mathrm{Cl}^{-}

Q10 Explain the following with reasons.(c) The solubility of glucose in water is increased by increasing the temperature.
Q10 Explain the following with reasons.(c) The solubility of glucose in water is increased by increasing the temperature.

Q10 Explain the following with reasons.(c) The solubility of glucose in water is increased by increasing the temperature.

iii) The \mathrm{pH} of 10^{-3} \mathrm{~mol} \mathrm{dm} -3 of an aqueous solution of \mathrm{H}_{2} \mathrm{SO}_{4} is(a) 3.0 (b) 2.7 (c) 2.0 (d) 1.5
iii) The  \mathrm{pH}  of  10^{-3} \mathrm{~mol} \mathrm{dm} -3 of an aqueous solution of  \mathrm{H}_{2} \mathrm{SO}_{4}  is(a)  3.0 (b)  2.7 (c)  2.0 (d)  1.5

iii) The \mathrm{pH} of 10^{-3} \mathrm{~mol} \mathrm{dm} -3 of an aqueous solution of \mathrm{H}_{2} \mathrm{SO}_{4} is(a) 3.0 (b) 2.7 (c) 2.0 (d) 1.5

(c) How do you calculate the solubility of a substance from the value of solubility product?
(c) How do you calculate the solubility of a substance from the value of solubility product?
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(c) How do you calculate the solubility of a substance from the value of solubility product?

15. "At equilibrium all processes come to a halt." What is wrong with this statement when applied to chemical systems?
15. "At equilibrium all processes come to a halt." What is wrong with this statement when applied to chemical systems?
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15. "At equilibrium all processes come to a halt." What is wrong with this statement when applied to chemical systems?

7. Consider the following equilibria:(i) 3 \mathrm{O}_{2(\varepsilon)} \rightleftharpoons 2 \mathrm{O}_{3(\alpha)} \Delta \mathrm{H}= positive(ii) \mathrm{H}_{2(s)} * \mathrm{I}_{2(\varepsilon)} 2 \mathrm{HI}{ }_{(\omega)} \Delta \mathrm{H}= positive(iii) 2 \mathrm{SO}_{2(s)} \cdot \mathrm{O}_{2(\varepsilon)} \rightleftharpoons 2 \mathrm{SO}_{3(s)} \Delta \mathrm{H}= negative(c) Which of the equilibria will not be affected by change in total pressure?
7. Consider the following equilibria:(i)  3 \mathrm{O}_{2(\varepsilon)} \rightleftharpoons 2 \mathrm{O}_{3(\alpha)}  \Delta \mathrm{H}=  positive(ii)  \mathrm{H}_{2(s)} * \mathrm{I}_{2(\varepsilon)} 2 \mathrm{HI}{ }_{(\omega)} \Delta \mathrm{H}=  positive(iii)  2 \mathrm{SO}_{2(s)} \cdot \mathrm{O}_{2(\varepsilon)} \rightleftharpoons 2 \mathrm{SO}_{3(s)}  \Delta \mathrm{H}=  negative(c) Which of the equilibria will not be affected by change in total pressure?
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7. Consider the following equilibria:(i) 3 \mathrm{O}_{2(\varepsilon)} \rightleftharpoons 2 \mathrm{O}_{3(\alpha)} \Delta \mathrm{H}= positive(ii) \mathrm{H}_{2(s)} * \mathrm{I}_{2(\varepsilon)} 2 \mathrm{HI}{ }_{(\omega)} \Delta \mathrm{H}= positive(iii) 2 \mathrm{SO}_{2(s)} \cdot \mathrm{O}_{2(\varepsilon)} \rightleftharpoons 2 \mathrm{SO}_{3(s)} \Delta \mathrm{H}= negative(c) Which of the equilibria will not be affected by change in total pressure?

(c) Write equilibrium constant expression for the following reactions(ii) \mathrm{Ag}^{+} (aq) +\mathrm{Fe}^{2+} (aq) \square \mathrm{Fe}^{3+} (aq) +\mathrm{Ag}(\mathrm{s})
(c) Write equilibrium constant expression for the following reactions(ii)   \mathrm{Ag}^{+} (aq)  +\mathrm{Fe}^{2+}  (aq)  \square  \mathrm{Fe}^{3+}  (aq)  +\mathrm{Ag}(\mathrm{s})
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(c) Write equilibrium constant expression for the following reactions(ii) \mathrm{Ag}^{+} (aq) +\mathrm{Fe}^{2+} (aq) \square \mathrm{Fe}^{3+} (aq) +\mathrm{Ag}(\mathrm{s})

9. At dynamic equilibriuma. the reaction stops to proceedb. the amounts of reactants and products are equalc. the speeds of the forward and reverse reactions are equald. the reaction can no longer be reversed
9. At dynamic equilibriuma. the reaction stops to proceedb. the amounts of reactants and products are equalc. the speeds of the forward and reverse reactions are equald. the reaction can no longer be reversed
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9. At dynamic equilibriuma. the reaction stops to proceedb. the amounts of reactants and products are equalc. the speeds of the forward and reverse reactions are equald. the reaction can no longer be reversed

When hydrogen reacts with iodine at 25^{\circ} \mathrm{C} to form hydrogen iodide by a reversible reaction as follows:\[\mathrm{H}_{2(\mathrm{~g})}+\mathrm{I}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{HI}_{(\mathrm{g})}\]The equilibrium concentrations are: \left[\mathrm{H}_{2}\right]=0.05 \mathrm{~mol} \mathrm{dm}^{-3} ; \left[\mathrm{I}_{2}\right]=0.06 \mathrm{~mol} \mathrm{dm}^{-3} ; and [\mathrm{HI}]=0.49 \mathrm{~mol} \mathrm{dm}^{-3} . Calculate the equilibrium constant for this reaction.
When hydrogen reacts with iodine at  25^{\circ} \mathrm{C}  to form hydrogen iodide by a reversible reaction as follows:\[\mathrm{H}_{2(\mathrm{~g})}+\mathrm{I}_{2(\mathrm{~g})}  \rightleftharpoons  2 \mathrm{HI}_{(\mathrm{g})}\]The equilibrium concentrations are: \left[\mathrm{H}_{2}\right]=0.05 \mathrm{~mol} \mathrm{dm}^{-3} ; \left[\mathrm{I}_{2}\right]=0.06 \mathrm{~mol} \mathrm{dm}^{-3} ;   and  [\mathrm{HI}]=0.49 \mathrm{~mol} \mathrm{dm}^{-3} . Calculate the equilibrium constant for this reaction.
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When hydrogen reacts with iodine at 25^{\circ} \mathrm{C} to form hydrogen iodide by a reversible reaction as follows:\[\mathrm{H}_{2(\mathrm{~g})}+\mathrm{I}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{HI}_{(\mathrm{g})}\]The equilibrium concentrations are: \left[\mathrm{H}_{2}\right]=0.05 \mathrm{~mol} \mathrm{dm}^{-3} ; \left[\mathrm{I}_{2}\right]=0.06 \mathrm{~mol} \mathrm{dm}^{-3} ; and [\mathrm{HI}]=0.49 \mathrm{~mol} \mathrm{dm}^{-3} . Calculate the equilibrium constant for this reaction.

Q3. Label the sentences as True or False.i) When a reversible reaction attains equilibrium both reactants and products are present in a reaction mixture.ii) The K_{c} of the reaction\[\mathrm{A}+\mathrm{B} \square \mathrm{C}+\mathrm{D}\]is given by\[\mathrm{K}_{\mathrm{c}}=\frac{[\mathrm{C}][\mathrm{D}]}{[\mathrm{A}][\mathrm{B}]}\]therefore it is assumed that\[[\mathrm{A}]=[\mathrm{B}]=[\mathrm{C}]=[\mathrm{D}]\]iii) A catalyst is a substance which increases the speed of the reaction and consequently increases the yield of the product.iv) Ionic product \mathrm{K}_{\mathrm{w}} of pure water at 25^{\circ} \mathrm{C} is 10^{-14} \mathrm{~mol}^{2} \mathrm{dm}^{-6} and is represented by an expression \mathrm{K}_{\mathrm{w}} =\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]=10^{-14} \mathrm{~mol}^{2} \mathrm{dm}^{-6} v) \mathrm{AgCl} is a sparingly soluble ionic solid in water. Its solution produces excess of \mathrm{Ag}^{+} and \mathrm{Cl}^{-} ions.
Q3. Label the sentences as True or False.i) When a reversible reaction attains equilibrium both reactants and products are present in a reaction mixture.ii) The  K_{c}  of the reaction\[\mathrm{A}+\mathrm{B} \square  \mathrm{C}+\mathrm{D}\]is given by\[\mathrm{K}_{\mathrm{c}}=\frac{[\mathrm{C}][\mathrm{D}]}{[\mathrm{A}][\mathrm{B}]}\]therefore it is assumed that\[[\mathrm{A}]=[\mathrm{B}]=[\mathrm{C}]=[\mathrm{D}]\]iii) A catalyst is a substance which increases the speed of the reaction and consequently increases the yield of the product.iv) Ionic product  \mathrm{K}_{\mathrm{w}}  of pure water at  25^{\circ} \mathrm{C}  is  10^{-14} \mathrm{~mol}^{2} \mathrm{dm}^{-6}  and is represented by an expression  \mathrm{K}_{\mathrm{w}}   =\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]=10^{-14} \mathrm{~mol}^{2} \mathrm{dm}^{-6} v)  \mathrm{AgCl}  is a sparingly soluble ionic solid in water. Its solution produces excess of  \mathrm{Ag}^{+} and  \mathrm{Cl}^{-} ions.
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Q3. Label the sentences as True or False.i) When a reversible reaction attains equilibrium both reactants and products are present in a reaction mixture.ii) The K_{c} of the reaction\[\mathrm{A}+\mathrm{B} \square \mathrm{C}+\mathrm{D}\]is given by\[\mathrm{K}_{\mathrm{c}}=\frac{[\mathrm{C}][\mathrm{D}]}{[\mathrm{A}][\mathrm{B}]}\]therefore it is assumed that\[[\mathrm{A}]=[\mathrm{B}]=[\mathrm{C}]=[\mathrm{D}]\]iii) A catalyst is a substance which increases the speed of the reaction and consequently increases the yield of the product.iv) Ionic product \mathrm{K}_{\mathrm{w}} of pure water at 25^{\circ} \mathrm{C} is 10^{-14} \mathrm{~mol}^{2} \mathrm{dm}^{-6} and is represented by an expression \mathrm{K}_{\mathrm{w}} =\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]=10^{-14} \mathrm{~mol}^{2} \mathrm{dm}^{-6} v) \mathrm{AgCl} is a sparingly soluble ionic solid in water. Its solution produces excess of \mathrm{Ag}^{+} and \mathrm{Cl}^{-} ions.

Q16 Sulphuric acid is the king of chemicals. It is produced by the burning of \mathrm{SO}_{2} to \mathrm{SO}_{3} through an exothermic reversible process.(b) What is the effect of pressure change on this reaction?
Q16 Sulphuric acid is the king of chemicals. It is produced by the burning of  \mathrm{SO}_{2}  to  \mathrm{SO}_{3}  through an exothermic reversible process.(b) What is the effect of pressure change on this reaction?
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Q16 Sulphuric acid is the king of chemicals. It is produced by the burning of \mathrm{SO}_{2} to \mathrm{SO}_{3} through an exothermic reversible process.(b) What is the effect of pressure change on this reaction?

(b) Why do the rates of forward reactions slow down when a reversible reaction approaches the equilibrium stage?
(b) Why do the rates of forward reactions slow down when a reversible reaction approaches the equilibrium stage?
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(b) Why do the rates of forward reactions slow down when a reversible reaction approaches the equilibrium stage?

EXAMPLE 3. In a reaction A+B=2 C when equilibrium was attained the concentration was [A]=[B]=4 moles / \mathrm{dm}^{3}[C]=6 \mathrm{moles} / \mathrm{dm}^{3} . Calculate the equilibrium constant K_{c} and the initial concentrations of A and B .
EXAMPLE 3. In a reaction  A+B=2 C  when equilibrium was attained the concentration was  [A]=[B]=4  moles  / \mathrm{dm}^{3}[C]=6 \mathrm{moles} / \mathrm{dm}^{3} . Calculate the equilibrium constant  K_{c}  and the initial concentrations of  A  and  B .
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EXAMPLE 3. In a reaction A+B=2 C when equilibrium was attained the concentration was [A]=[B]=4 moles / \mathrm{dm}^{3}[C]=6 \mathrm{moles} / \mathrm{dm}^{3} . Calculate the equilibrium constant K_{c} and the initial concentrations of A and B .

4. When nitrogen reacts with hydrogen to form ammonia the equilibrium mixture contains 0.31 \mathrm{~mol} \mathrm{dm}^{-3} and 0.50 \mathrm{~mol} \mathrm{dm}^{-3} of nitrogen and hydrogen respectively. If the \mathrm{K}_{\mathrm{c}} is 0.50 \mathrm{~mol}^{-} { }^{2} \mathrm{dm}^{6} what is the equilibrium concentration of ammonia?
4. When nitrogen reacts with hydrogen to form ammonia the equilibrium mixture contains  0.31 \mathrm{~mol} \mathrm{dm}^{-3}  and  0.50 \mathrm{~mol} \mathrm{dm}^{-3}  of nitrogen and hydrogen respectively. If the  \mathrm{K}_{\mathrm{c}}  is  0.50 \mathrm{~mol}^{-}   { }^{2} \mathrm{dm}^{6}  what is the equilibrium concentration of ammonia?
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4. When nitrogen reacts with hydrogen to form ammonia the equilibrium mixture contains 0.31 \mathrm{~mol} \mathrm{dm}^{-3} and 0.50 \mathrm{~mol} \mathrm{dm}^{-3} of nitrogen and hydrogen respectively. If the \mathrm{K}_{\mathrm{c}} is 0.50 \mathrm{~mol}^{-} { }^{2} \mathrm{dm}^{6} what is the equilibrium concentration of ammonia?

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