CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 12 - MCQExams.com

Compound A$$_{(l)}$$ and B$$_{(l)}$$ function as a weak acid and weak base respectively when dissolved in water. When pure A$$_{(l)}$$ is dissolved in anhydrous B$$_{(l)}$$, A will function as:
  • an acid
  • a base
  • a stronger acid than when dissolved in $$H_2O$$
  • a stronger base than when it is dissolved in $$H_2O$$
Calculate the $${OH}^{-}$$ concentration and the $${H}_{3}{PO}_{4}$$ concentration of a solution prepared by dissolving $$0.1$$ mol of $${Na}_{3}{PO}_{4}$$ in sufficient water to make $$1L$$ of solution.
$${K}_{1}=7.1\times {10}^{-3}$$, $${K}_{2}=6.3\times {10}^{-8}$$; $${K}_{3}=4.5\times {10}^{-13}$$
  • $$[{OH}^{-}]=1.36\times {10}^{-2}M$$, $$[{H}_{3}{PO}_{4}]=2.96\times {10}^{-18}M$$
  • $$[{OH}^{-}]=3.73\times {10}^{-2}M$$, $$[{H}_{3}{PO}_{4}]=5.93\times {10}^{-18}M$$
  • $$[{OH}^{-}]=5.9\times {10}^{-2}M$$, $$[{H}_{3}{PO}_{4}]=6.45\times {10}^{-18}M$$
  • $$[{OH}^{-}]=6.45\times {10}^{-2}M$$, $$[{H}_{3}{PO}_{4}]=5.9\times {10}^{-18}M$$
A solution contains $$HCl$$, $${Cl}_{2}HCCOOH$$ and $${CH}_{3}COOH$$ at concentrations $$0.09M$$ in $$HCl$$, $$0.09M$$ in $${Cl}_{2}HCCOOH$$ and $$0.1M$$ in $${CH}_{3}COOH$$, $$pH$$ for the solution is $$1$$. Ionization constant of $${CH}_{3}COOH={10}^{-5}$$. What is the magnitude of $$K$$ for dichloroacetic acid?
  • $${k}{{a}_{2}}=1.25\times {10}^{-2}$$
  • $${k}{{a}_{2}}=1.25\times {10}^{-1}$$
  • $${k}{{a}_{2}}=1.25\times {10}^{-4}$$
  • $${k}{{a}_{2}}=1.25\times {10}^{-3}$$
At $${60}^{o}C$$, pure water has $$[{H}_{3}{O}^{+}]={10}^{-6.7}mol/lit$$.What is the value of $${K}_{W}$$ at $${60}^{o}C$$ :-
  • $${10}^{-6}$$
  • $${10}^{-12}$$
  • $${10}^{-67}$$
  • $${10}^{-13.4}$$
At $$90^oC$$, pure water $$[H_3O^{\oplus}]$$ as $$10^{-6} mol\, L^{-1}$$ what is the value of $$K_w$$ at $$90^oC$$ ?
  • $$10^{-6}$$
  • $$10^{-12}$$
  • $$10^{-14}$$
  • $$10^{-8}$$
The $$pH$$ of a solution of sodium hydroxide isWhat will be its $$pH$$ when this solution is diluted?
  • Less than 9
  • More than 9
  • Equal to 9
  • Equal to 10
The solubility of $$Hg{I}_{2}$$ in water decreases in presence of $$KI$$.

State whether the given statement is true or false.
  • True
  • False
The colour of a salt depends upon its
  • density
  • composition
  • surface temperature
  • radius
A buffer solution can be prepared from a mixture of:

(i) Sodium acetate and acetic acid in water
(ii) Sodium acetate and hydrochloric acid in water
(iii) Ammonia and ammonium chloride in water
(iv) Ammonia and sodium hydroxide in water
  • (i), (ii)
  • (ii), (iii)
  • (iii), (iv)
  • (i), (iii)
Which one of the following statements is not correct?
  • The pH of $$1.0 \times {10}^{-8} M\ HCl$$ is less than $$7$$
  • The ionic product of water at $$25^0C$$ is $$1.0 \times {10}^{-14}\ {mol}^{2} {L}^{-2}$$
  • $${Cl}^{-}$$ is a Lewis acid
  • Bronsted-Lowry theory cannot explain the acidic character of $$Al{Cl}_{3}$$
$$\displaystyle { BaCl }_{ 2 }$$ dissociates in water to give one $$\displaystyle { Ba }^{ 2+ }$$ ion and two $$\displaystyle { Cl }^{ - }$$ ions. If concentrated $$\displaystyle HCl$$ is added to this solution :
  • $$\displaystyle \left[ { Ba }^{ 2+ } \right] $$ increases
  • $$\displaystyle \left[ { Ba }^{ 2+ } \right] $$ remains constant
  • $$\displaystyle \left[ { OH }^{ - } \right] $$ increases
  • The number of moles of undissociated $$\displaystyle { BaCl }_{ 2 }$$ increases
  • $$\displaystyle \left[ { H }^{ + } \right] $$ decreases
Statement I: At equilibrium, the concentration of reactants and products remains constant.
Statement II: At equilibrium, the rates of the forward and reverse reactions are equal.
  • Statement I and Statement II are true and Statement II is correct explanation of Statement I
  • Statement I and Statement II are true and Statement II is not correct explanation of Statement I
  • Statement I is true and Statement II is false
  • Statement I is false and Statement I is true
Which of the following salts will have maximum cooling effect when $$0.5$$ mole of the salt is dissolved in same amount of water. Integral heat of solution at $$298\ K$$ is given for each salt.
  • $$KNO_{3}  (\Delta =35.4\ kJ\ mol^{-1})$$
  • $$NaCl  (\Delta =5.35\ kJ\ mol^{-1})$$
  • $$HBr  (\Delta =83.3\ kJ\ mol^{-1})$$
  • $$KOH  (\Delta =55.6\ kJ\ mol^{-1})$$
At 298 K $$0.01 M\ { NH }_{ 4 }OH$$ solution is $$4.3\%$$ ionised.The ionization constant of $${ NH }_{ 4 }OH $$ is :
  • $$1.84\times10^{-5}$$
  • $$2.05\times 10^{-5}$$
  • $$1.62\times 10^{-4}$$
  • $$1.84\times 10^{-4}$$
Which of the following symbol represents acid dissociation constant?
  • $$\displaystyle pH$$
  • $$\displaystyle pOH$$
  • $$\displaystyle { K }_{ a }$$
  • $$\displaystyle { K }_{ b }$$
  • $$\displaystyle { K }_{ w }$$
Which of the following will form a buffer solution of 1L solution?
  • 0.2 mol of $$\displaystyle HCl$$ and 0.1 mole of $$\displaystyle { K }_{ 2 }{ SO }_{ 3 }$$
  • 0.2 mol of $$\displaystyle NaOH$$ and 0.4 mol of $$\displaystyle HF$$
  • 0.1 mol of $$\displaystyle HBr$$ and 0.1 mol of $$\displaystyle { Ba\left( OH \right) }_{ 2 }$$
  • 0.4 mol of $$\displaystyle HCl$$ and 0.2 mol of $$\displaystyle { NH }_{ 3 }$$
  • 0.2 mol of $$\displaystyle NaOH$$ and 0.4 mol of $$\displaystyle HCl$$
Assertion: AgCl will not dissolve in a concentrated solution.
Reason: The chloride ions from NaCl suppress the solubility of AgCl.
  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  • Assertion is true but Reason is false
  • Assertion is false but Reason is true
  • Both Assertion and Reason are false
From the give options, which of the following compound will make best buffer solution?
  • $${ H }_{ 2 }O,\ 1\ M\ NaOH,\ 1\ M\ { H }_{ 2 }S{ O }_{ 4 }$$
  • $${ H }_{ 2 }O,\ \ 1\ M\ C{ H }_{ 3 }COOH,\ 1\ M\ { Na }^{ + }C{ H }_{ 3 }CO{ O }^{ - }$$
  • $${ H }_{ 2 }O,\ 1\ M\ C{ H }_{ 3 }COOH,\ 6\ M\ { Na }^{ + }C{ H }_{ 3 }CO{ O }^{ - }$$
  • $${ H }_{ 2 }O,\ 1\ M\ C{ H }_{ 3 }COOH,\ 1\ M\ NaOH$$
A student performed an experiment to determine the solubility of a salt a various temperatures. The data from the experiment can be seen below:
TrialTemp ($$\displaystyle ^{ \circ  }{ C }$$)Solubility in 100 g water
12044
23058
34067
45062
56084
Which trial seems to be in error?
  • 1
  • 2
  • 3
  • 4
  • 5
The $$K_{sp}$$ for $$Mg(OH)_2$$ in water is $$1.2 \times 10^{-11}$$. In an acidic solution, if the $$Mg^{2+}$$ concentration is $$1.2 \times 10^{-5} mol/L$$, what is the pH at which $$Mg(OH)_2$$ just begins to precipitate?
  • 3
  • 4
  • 5
  • 11
  • 12
At 298K, $$\displaystyle { K }_{ W }$$ of water is : 
  • $$\displaystyle 1\times { 10 }^{ -14 }$$
  • $$\displaystyle 1\times { 10 }^{ -17 }$$
  • $$\displaystyle 1\times { 10 }^{ -1 }$$
  • $$\displaystyle 1\times { 10 }^{ -7 }$$
Assertion: Water makes a good buffer.
Reason: A good buffer will resist changes in $$\displaystyle pH$$.

  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion

  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

  • Assertion is true but Reason is false

  • Assertion is false but Reason is true

  • Both Assertion and Reason are false

The following reaction occurs in a beaker: $$\displaystyle { Ag }^{ + }\left( aq \right) +{ Cl }^{ - }\left( aq \right) \rightarrow AgCl\left( s \right) $$. If a solution of sodium chloride were added to this beaker,
  • The solubility of the sodium chloride would decrease
  • The reaction would shift to the left
  • The concentration of silver ions in solution would increase
  • The solubility of the silver chloride would decrease
  • The equilibrium would not shift at all
An acidic buffer solution has $$[HA]=1.0\,M$$ and $$[NaA]=1.0M$$. To $$(10+x)mL$$ of this buffer solution $$9\,mL$$ of $$1.0\,M\,HCl$$ is added so that $$pH$$ changes by one unit. The value of x is
  • $$0.1$$
  • $$10$$
  • $$1.5$$
  • $$1.0$$
$$MgC{l}_{2}$$ and $$NaCl$$ are both salts that are used to treat roads. Which salt will have the greatest effect on the freezing point and why?
  • NaCl because i = 2
  • MgCl2 because i = 3
  • MgCl2 because i = 2
  • NaCl because i = 3
  • Both salts would have the same effect
Which compound is used for bleaching cloths in laundry?
  • Bleaching powder
  • Washing powder
  • Baking powder
  • Plaster of Paris
The solubility of silver chloride ___________ in the presence of sodium chloride because of __________.
  • increases; common ion effect
  • increases; aldol condensation
  • decreases; common ion effect
  • decreases; aldol condensation
Uses of bleaching powder is/are:
  • It is used as a disinfectant in sterilization of water
  • It is used to bleach straw, ivory
  • It is used as an oxidising agent in industry
  • It is used for making wool unshrinkable
Assertion: When a non-volatile solute is added to pure water, the vapor pressure of the water will decrease.
Reason: All solutes dissociate into positive and negative ions.
  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  • Assertion is true but Reason is false
  • Assertion is false but Reason is true
  • Both Assertion and Reason are false
Concentrated strong acid is added to a solid mixture of 0.015 mole samples of $$Fe(OH)_2$$ and $$Ca(OH)_2$$ placed in one litre of water. At what value of pH will the dissolution of each hydroxide be complete? (Assume negligible volume change)
$$K_{sp}[Fe(OH)_2]=7.9\times 10^{-15}$$ and $$K_{sp}[Cu(OH)_2]=1.6\times 10^{-19}$$
  • 6.67
  • 7.86
  • 8.86
  • 7.26
What is the net effect of the common ion?
  • It reduces the solubility of the solute in the solution.
  • It reduces the increases of the solute in the solution.
  • It causes more product to be made.
  • It causes more ions to form.
  • There is no net effect overall.
$$pK_{b}$$ of $$NH_{3}$$ is $$4.74$$ and $$pK_{b}$$ of $$A^{-}, B^{-}$$ and $$C^{-}$$ are $$4, 5$$ and $$6$$ respectively. Aqueous solution of $$0.01\ M$$ has $$pH$$ in the increasing order.
  • $$NH_{4}A < NH_{4}B < NH_{4}C$$
  • $$NH_{4}C < NH_{4}B < NH_{4}A$$
  • $$NH_{4}C < NH_{4}A < NH_{4}B$$
  • All have equal $$pH$$
A litre of solution is saturated with $$AgCl$$. To this solution if $$1.0\times { 10 }^{ -4 }$$ mole of solid $$NaCl$$ is added, what will be the $$\left[ { Ag }^{ + } \right] $$ assuming no volume change?
  • More
  • Less
  • Equal
  • Zero
Which mixture forms a buffer when dissolved in 1 L of water?
  • 0.2mol NaOH + 0.2 mol HBr 

  •  0.2mol NaCl + 0.3mol HCl 

  •  0.4 mol $$HNO_2$$ + 0.2mol NaOH 

  •  0.5 mol $$NH_3$$ + 0.5mol HCl 
Equilibrium constant for the reaction,  $$NH_{4}OH + H^{+}\rightleftharpoons NH_{4}^{+} + H_{2}O$$ is $$1.8\times 10^{9}$$. Hence, equilibrium constant for $$NH_{3}(aq) + H_{2}O \rightleftharpoons NH_{4}^{+} + OH^{-}$$ is:
  • $$1.8\times 10^{-5}$$
  • $$1.8\times 10^{5}$$
  • $$1.8\times 10^{-9}$$
  • $$5.59\times 10^{-10}$$
The solubility of $$AgI$$ in $$NaI$$ solution is less than that in pure water because:
  • $$Agl$$ forms complex with $$Nal$$
  • of common ion effect
  • solubility product of $$Agl$$ is less
  • the temperature of the solution decreases
1.0 g of a weak monobasic acid ($$HA$$), when dissolved in 150 mL water, lowers the freezing point by $$0.186^o C$$. Also 1.0 g of the same acid required 125 mL of a 0.10N Nate solution for complete neutralisation. Determine dissociation constant $$(k_a)$$ of the weak acid. $$k_f$$ of water is 1.86 K kg $$mol^{-1}$$. 
  • $$4.16 \times 10^{-3}$$
  • $$2.38 \times 10^{-6}$$
  • $$6.43 \times 10^{-3}$$
  • $$3.78 \times 10^{-6}$$
When common salt is added to a saturated solution of soap, soap is precipitated. This is based on the principle of
  • Common ion effect
  • Principle of solubility product
  • Adsorption from solution
  • Peptisation
Which among the following groups is acidic in nature?
  • Grapes and distilled water
  • Soap solution and vinegar
  • Milk of magnesia and milk
  • Ant sting and vinegar
During electrolysis of molten NaCl, some water was added. What will happen?
  • Electrolysis will stop
  • Hydrogen will be evolved
  • Some amount of caustic soda will be formed
  • A fire is likely
For the following equilibrium, $$N_2O_4\rightleftharpoons 2NO_2$$ in gaseous phase, $$NO_2$$ is 50% of the total volume when equilibrium is set up. Hence, percent of dissociation of $$N_2O_4$$ is:
  • 50%
  • 25%
  • 66.66%
  • 33.33%
Very strong acids, such as $$HNO_3$$ and $$HCl$$, appear to be equally strong in water. This "leveling effect" of water is because
  • $$OH^-$$ is a stronger base than the conjugate bases of $$HNO_3$$ and $$HCl$$
  • $$H_3O^+$$ is a stronger acid than $$HNO_3$$ and $$HCl$$
  • $$H_2O$$ is a stronger base than the conjugate bases of $$HNO_3$$ and $$HCl$$
  • $$H_2O$$ is a weaker base than the conjugate bases of $$HNO_3$$ and $$HCl$$
Which of the following pairs will show common ion effect?
  • Barium chloride + barium sulphate
  • Silver cyanide + potassium nitrite
  • Ammonium hydroxide + ammonium chloride
  • Sodium chloride + hydrogen chloride
The hydrated salt $$Na_{2}SO_{4}, 10H_{2}O$$ undergoes $$X\%$$ loss in weight on heating and becomes anhydrous. The value of $$X$$ will be:
  • $$10$$
  • $$45$$
  • $$56$$
  • $$70$$
(A) pH of $$10^{-7}$$ M NaOH solution exists between 7 to 7.3 at $$25^o C$$.
(R) Due to common ion effect ionization of water is suppressed. 
  • Both (R) and (A) are true and reason is the correct explanation of assertion
  • Both (R) and (A) are true but reason is not correct explanation of assertion
  • Assertion (A) is true but reason (R) is false
  • Assertion (A) and reason (R) both are false
  • Assertion (A) is false but reason (R) is true
Which of the following mixtures will be buffer?
  • $${ CH }_{ 3 }COOH+{ CH }_{ 3 }COO{ NH }_{ 4 }$$
  • $$HCl+NaCl$$
  • Borax+boric acid
  • $${ CH }_{ 3 }COOH+{ CH }_{ 3 }COONa$$
(A) If water is heated to 350 K, then pOH will increase to
(R) $$K_w$$ increases with increase in temperature.
  • Both (R) and (A) are true and reason is the. correct explanation of assertion
  • Both (R) and (A) are true but reason is not correct explanation of assertion
  • Assertion (A) is true but reason (R) is false
  • Assertion (A) and reason (R) both are false
  • Assertion (A) is false but reason (R) is true
An excess of $$Ag_2CrO_4(s)$$ is added to a $$5\times 10^{-3}M$$ $$K_2CrO_4$$ solution. The concentration of $$Ag^+$$ in the solution is closest to.[Solubility product for $$Ag_2CrO_4=1.1\times 10^{-12}$$]
  • $$2.2\times 10^{-10}$$M
  • $$1.5\times 10^{-5}$$M
  • $$1.0\times 10^{-6}$$M
  • $$5.0\times 10^{-3}$$M
Which of the following would dissolve $$Pb(OH)_{2}$$ more than pure water?
  • Buffer solution having $$pH = 6$$
  • $$0.01\ M\ PbCl_{2}$$ solution
  • $$0.01\ M\ NH_{4}OH$$ solution
  • All of the above
The solubility product constant $$Ksp$$ of $$Mg(OH)_{2}$$ is $$9.0\times 10^{-12}$$. If a solution is $$0.010\ M$$ with respect to $$Mg^{2+}$$ ion. What is the maximum hydroxide ion concentration which could be present without causing the precipitation of $$Mg(OH)_{2}$$?
  • $$1.5\times 10^{-7}M$$
  • $$3.0\times 10^{-7}M$$
  • $$1.5\times 10^{-5}M$$
  • $$3.0\times 10^{-5}M$$
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