CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 8 - MCQExams.com

The reaction,$$Pb(OH{ ) }_{ 2 }+HN{ O }_{ 3 }\rightarrow Pb(OH)N{ O }_{ 3 }+{ H }_{ 2 }O $$ shows that $$Pb(OH)N{ O }_{ 3 }$$ is
  • acidic salt
  • basic salt
  • base
  • acid
A buffer solution is used in:
  • preparation of potash alum
  • the removal of $${ PO }_{ 4 }^{ 3- }$$ ions
  • increasing the pH value of a solution
  • precipitation of $$Cr{ \left( OH \right) }_{ 3 }$$ from $$Cr{ Cl }_{ 3 }$p
Which of the following expressions is not true?
  • $$\left[ { H }^{ + } \right] =\left[ { OH }^{ - } \right] =\sqrt { { K }_{ w } } $$ for a neutral solution
  • $$\left[ { H }^{ + } \right] >\sqrt { { K }_{ w } } $$ and $$\left[ { OH }^{ - } \right] <\sqrt { { K }_{ w } } $$ for an acidic solution
  • $$\left[ { H }^{ + } \right] <\sqrt { { K }_{ w } } $$ and $$\left[ { OH }^{ - } \right] >\sqrt { { K }_{ w } } $$ for an alkaline solution
  • $$\left[ { H }^{ + } \right] =\left[ { OH }^{ - } \right] ={ 10 }^{ -7 }M$$ for a neutral solution at all temperatures
$$1M$$ $$NaCl$$ and $$1M$$ $$HCl$$ are present in an aqueous solution. The solution is:
  • Not a buffer solution with $$pH< 7$$
  • Not a buffer solution with $$pH> 7$$
  • A buffer solution with $$pH< 7$$
  • A buffer solution with $$pH= 7$$
Which of the following will function as buffer?
  • $$NaCl+NaOH$$
  • Borax$$+$$boric acid
  • $$Na{ H }_{ 2 }{ PO }_{ 4 }+NaH{ PO }_{ 4 }$$
  • $${ NH }_{ 4 }Cl+{ NH }_{ 4 }OH$$
When strong base $$(NaOH)$$ is added to the weak acid (acetic acid, $${ CH }_{ 3 }COOH$$), then dissociation of acetic acid increases; this effect is known as:
  • Common ion effect
  • Reverse ion effect
  • Saltation effect
  • Solubility effect
The weak acid, $$HA$$ has a $${K}_{a}$$ of $$1.00\times { 10 }^{ -5 }$$. If $$0.1$$ mol of this acid is dissolved in one litre of water, the percentage of acid dissociated at equilibrium is closet to:
  • $$1$$%
  • $$99.9$$%
  • $$0.1$$%
  • $$99$$%
Aqueous solution of $$H{ NO }_{ 3 },KOH,{ CH }_{ 3 }COOH$$ and $${CH}_{3}COONa$$ of identical concentrations are provided. The pair(s) of solutions which form a buffer upon mixing is (are):
  • $$H{ NO }_{ 3 }$$ and $${ CH }_{ 3 }COOH$$
  • $$KOH$$ and $${ CH }_{ 3 }COONa$$
  • $$H{ NO }_{ 3 }$$ and $${ CH }_{ 3 }COONa$$
  • $${ CH }_{ 3 }COOH$$ and $${ CH }_{ 3 }COONa$$
If concentration of two acids are some, their relative strengths can be compared by:
  • $${ \alpha }_{ 1 }/{ \alpha }_{ 2 }$$
  • $$K_{ 1 }/K_{ 2 }$$
  • $${ \left[ { H }^{ + } \right] }_{ 1 }/{ \left[ { H }^{ + } \right] }_{ 2 }$$
  • $$\sqrt { K_{ 1 }/K_{ 2 } } $$
For dissociation constant $$(K)$$ and ionic product $$({K}_{w})$$ of water which is correct?
  • $$K>{ K }_{ w }$$
  • $${ K }_{ w }>K$$
  • $${ K }_{ w }=K$$
  • None of these
Which mixture forms a buffer when dissolved in $$1\ L$$ of water?
  • $$0.2\ mol\ NaOH+0.2\ mol \ HBr$$
  • $$0.2\ mol \ NaCl+0.3\ mol\ HCl$$
  • $$0.4\ mol\ H{NO}_{2}+0.2\ mol\ NaOH$$
  • $$0.5\ mol\ {NH}_{3}+0.5\ mol\ HCl$$
Which of the following statements is/are correct about the ionic product of water?
  • $$K$$ (equilibrium constant of water) $$< { K }_{ w }$$ (ionic product of water)
  • $$pK>p{ K }_{ w }$$
  • At $$300K$$, $${ K }_{ w }$$ of water becomes $${10}^{-12}$$
  • Ionic product of water at $${ 25 }^{ o }C$$ is $${ 10 }^{ -14 }$$
Which of the following is not a buffer solution ?
  • $$CH_3COOH + CH_3COONa$$
  • $$H_3BO_3+Na_3BO_3$$
  • $$HClO_4 + NaClO_4$$
  • $$NH_4OH+ (NH_4)_2SO_4$$
The solubility of $${ A }_{ 2 }{ X }_{ 5 }$$ is $$x\ mol\ { dm }^{ -3 }$$. Its solubility product is:
  • $$36{ x }^{ 6 }$$
  • $$64\times { 10 }^{ 4 }{ x }^{ 7 }$$
  • $$126{ x }^{ 7 }$$
  • $$1.25\times { 10 }^{ 4 }{ x }^{ 7 }$$
The solution of blue vitriol in water is acidic because:
  • $$CuSO_4$$ reacts with water
  • $$Cu^{2+}$$ reacts with water
  • $$SO^{2-}_4$$ reacts with water
  • $$CuSO_4$$ removes $$OH^-$$ ions from water
The degree of dissociation of water at $${ 25 }^{ o }C$$ is $$1.8\times { 10 }^{ -7 }$$% and density is $$1.0g{ cm }^{ -3 }$$. The ionic constant for water is:
  • $$1.0\times { 10 }^{ -14 }$$
  • $$2.0\times { 10 }^{ -16 }$$
  • $$1.0\times { 10 }^{ -16 }$$
  • $$1.0\times { 10 }^{ -8 }$$
What do you mean by buffer solution?
  • Buffer solution have no $$pH$$
  • Its $$pH$$ changes very little when a small amount of acid or base is added to the it
  • Its $$pH$$ changes very largely when a small amount of acid or base is added to the it
  • All solutions are buffer
The pH of a $$0.1M$$ aqueous solution of a weak acid ($$HA$$) is $$3$$. Its degree of dissociation is
  • $$1$$%
  • $$10$$%
  • $$50$$%
  • $$25$$%
To prepare a buffer solution of $$pH = 4.04$$, amount of Barium acetate to be added to $$100 mL$$ of $$0.1$$ M acetic acid solution [ $$pK_0(CH_3COO^-) =9.26$$] is:
  • $$0.05$$ mole
  • $$0.025$$ mole
  • $$0.1$$ mole
  • $$0.005$$ mole
Assuming each salt to be 90% dissociated, which of the following will have highest boiling point.
  • Decimolar $$Al_2(SO_4)_3$$
  • Decimolar $$BaCl_2$$
  • Decimolar $$Na_2SO_4$$
  • A solution obtained by mixing equal volumes of (B) and (C)
The concentration of $$[H^{+}]$$ and concentration of $$[OH^{-}]$$ of a $$0.1\ M$$ aqueous solution of $$2$$M ionised weak acid is: [ionic product of water $$=1\times 10^{-14}]$$.
  • $$0.02\times 10^{-3}M$$ and $$5\times 10^{-11}M$$
  • $$1\times 10^{-3}M$$ and $$3\times 10^{-11}M$$
  • $$2\times 10^{-3}M$$ and $$5\times 10^{-12}M$$
  • $$3\times 10^{-2}M$$ and $$4\times 10^{-13}M$$
How many grams of $$CO_2$$ gas is dissolved in a $$1$$ lt bottle of carbonated water if the manufacturer uses a pressure of $$2.4$$ atmosphere in the bottling process at $$25^o$$C? Given $$K_H$$ of $$CO_2$$ water $$=29.76$$ atm/mole/l at $$25^o$$C.
  • $$3.52$$
  • $$4.2$$
  • $$3.1$$
  • $$2.5$$
Buffer solution $$A$$ of a weak monoprotic acid and its sodium salt in the concentration ratio $$x : y$$ has $$pH = (pH)$$,. Buffer solution $$B$$ of the same acid and its sodium salt in the concentration ratio $$y : x$$ has $$pH = (pH)_{2}$$. If $$(pH)_{2} - (pH)_{1} = 1$$ unit and $$(pH)_{1} + (pH)_{2} = 9.5\ units$$, then:
  • $$\dfrac {x}{y} = 3.162$$
  • $$pK_{a} = 4.75$$
  • $$\dfrac {x}{y} = 2.36$$
  • $$pK_{a} = 5.25$$
To prepare a buffer of pH 8.26 amount of $$({ NH }_{ 4 }{ ) }_{ 2 }{ SO }_{ 4 }$$ to be added to 500 mL of 0.01 M $${ NH }_{ 4 }OH$$ solution is : $$[pK_{ a }({ NH }_{ 4 }^{ + })\ =9.26]$$
  • 0.05 mole
  • 0.025 mole
  • 0.10 mole
  • 0.005 mole
A buffer solution made up of $$BOH$$ and $$BCl$$ of total molarity 0.29 M has $$pH = 9.6$$ and $${ K }_{ b }=1.8\ \times \ { 10 }^{ -5 }$$. Concentration of salt and base respectively is:
  • 0.09 M and 0.2 M
  • 0.2 M and 0.09 M
  • 0.1 M and 0.19 M
  • 0.19 M and 0.1 M
For preparing a buffer solution of $$pH=7.0$$, which buffer system you will choose:
  • $$H_{3}PO_{4},H_{2}PO_4{^-}$$
  • $$H_{2}PO_4{^-},\ HPO^{2-}_{4}$$
  • $$HPO^{2-}_{4},PO^{3-}_{4}$$
  • $$H_{3}PO_{4},PO^{3-}_{4}$$
The pH of 0.2 M solution of acid HQ =Then the value of $$K_{a}$$  for HQ will be 
  • $$10^{-7}$$
  • $$5\times10^{-6}$$
  • $$5\times10^{-3}$$
  • $$3\times10^{-3}$$
The total number of different kind of buffers obtained during the titration of $$H_3PO_4$$ with $$NaOH$$ are:
  • $$3$$
  • $$1$$
  • $$2$$
  • $$0$$
At a temperature under high pressure $$K_w(H_2O) \, = \, 10^{10}$$, a solution of pH 5.4 is said to be:
  • Acidic
  • Basic
  • Neutral
  • Amphitoric
At what temperature liquid water will be in equilibrium with water vapour?
$$\Delta H_{vap} = 40.73 \ kJ \ mol^{-1}$$, $$\Delta S_{vap} = 0.109 \ kJ \ K^{-1} \ mol^{-1}$$, 
  • 282.4 K
  • 373.6 K
  • 100 K
  • 400 K
Several blocks of magnesium are fixed to the bottom of a ship to
  • Prevent puncture by undersea rocks
  • Keeps away the sharks
  • Prevent action of water and salts
  • Make the ship lighter
What will be the value of pH of $$0.01 mol\  dm^{-3} CH_3COOH (K_a = 1.74 \times 10^{-5})$$?
  • $$3.4$$
  • $$3.6$$
  • $$3.9$$
  • $$3.0$$
Choose the correct answer from the alternatives given.

The human stomach produces acid $$X$$ which helps in the digestion of food. Acid $$X$$ is _______.
  • acetic acid
  • methanoic acid
  • hydrochloric acid
  • citric acid
An acid $$HA$$ ionizes as, $$HA\rightleftharpoons H^++A^-$$. The pH of $$1.0$$M solution is $$5$$. Its dissociation constant would be:
  • $$1\times 10^{-10}$$
  • $$5$$
  • $$5\times 10^{-8}$$
  • $$1\times 10^{-5}$$
At 373 K, steam and water are in equilibrium and $$\Delta H$$ = 40.98 kJ $$mol^{-1}$$.What will be  $$\Delta S$$ fro conversion of water into steam?
$$H_2O_{(l)} \rightarrow H_2O_{(g)}$$
  • 109.8 J $$K^{-1}mol^{-1}$$
  • 31 J $$K^{-1}mol^{-1}$$
  • 21.98 J $$K^{-1}mol^{-1}$$
  • 326 J $$K^{-1}mol^{-1}$$
Which one of the following mixture does not act as a buffer solution?
  • Boric acid and borax
  • Sodium phosphate & disodium hydrogen phosphate
  • Sodium propionate and propionic acid
  • Sodium acetate and sodium propionate
Which of the following graphs are correct for the give reaction
$${H}_{2}(g)+{CO}_{2}(g)\rightleftharpoons {H}_{2}(g)+CO(g)$$
Assume initially only $${H}_{2}$$ and $${CO}_{2}$$ are present
Which of the following will not show common ion effect on addition of $$HCl$$ ?
  • $$CH_3COOH$$
  • $$H_2S$$
  • $$C_6H_5COOH$$
  • $$H_2SO_4$$
The equivalent conductance of $$M/32$$ solution of monobasic acid is $$8.0$$ mho $$cm^2$$ and at infinite dilution is $$400$$ mho $$cm^2$$. The dissociation constant of this acid is:
  • $$1.25\times 10^{-5}$$
  • $$1.25\times 10^{-6}$$
  • $$6.25\times 10^{-4}$$
  • $$1.25\times 10^{-4}$$
For preparing a buffer solution of $$pH=7.0$$, which buffer system you will choose?
  • $${ H }_{ 3 }{ PO }_{ 4 },{ H }_{ 2 }{ PO }_{ 4 }^{ - }$$
  • $${ H }_{ 2 }{ PO }_{ 4 }^{ - }, { HPO }_{ 4 }^{ 2- }$$
  • $${ HPO }_{ 4 }^{ 2- },{ PO }_{ 4 }^{ 3- }$$
  • $${ H }_{ 3 }{ PO }_{ 4 },{ PO }_{ 4 }^{ 3- }$$
A buffer solution with $$ pH =9 $$ is to be prepared by mixing $$NH_4CI $$ and $$ NH_4OH $$. Calculate the number of moles of $$NH_4CI $$ that should be added to one litre pf $$1.0 M $$ $$ NH_4OH $$ . $$[K_b = 1.8 \times 10^{-5}]$$
  • $$3.4 $$
  • $$2.6 $$
  • $$1.5 $$
  • $$1.8 $$
Which of the following solutions when added to $$1L$$ of a $$0.1\ M$$ $${ CH }_{ 3 }COOH$$ solution will cause no change in either the degree of dissociation of $${ CH }_{ 3 }COOH$$ or the pH of the solution $$[Ka = 1.6\ \times\  10^{-5}$$ for $${ CH }_{ 3 }COOH]$$ 
  • $$0.6\ mM$$ $$HCOOH (K_{a}=8\ \times 10^{-4})$$
  • $$0.1\ M\ CH_{3}COONa$$
  • $$0.1$$ of $$2mM\ HCI$$
  • $$0.1 M$$ $${ CH }_{ 3 }COOH$$
Find the percentage of ionisation of 0.2 M acetic acid solution, whose dissociation constant is $$1 .8 \times 10^{-5}$$ .
  • 0.198
  • 0.290
  • 0.950
  • none of these
$${ H }_{ 3 }{ PO }_{ 4 }$$ is a tribasic acid and one of its salt is $${ NaH }_{ 2 }{ PO }_{ 4 }$$ What volume of $$1M\quad NaOH$$ solution should be added to $$12g\ { NaH }_{ 2 }{ PO }_{ 4 }$$ to convert it into $${ Na }_{ 3 }{ PO }_{ 4 }$$? ($$at.wt$$ of $$P=31$$)
  • $$100\ ml$$
  • $$200\ ml$$
  • $$80\ ml$$
  • $$300\ ml$$
A monoprotic acid in $$100\ M$$ solution is $$0.001\%$$ ionized. The dissociation constant of this acid is:
  • $$1.0\ \times 10^{-3}$$
  • $$1.0\ \times 10^{3}$$
  • $$1.0\ \times 10^{-8}$$
  • $$1.0\ \times 10^{-10}$$
Ionization constant $$({ K }_{ a })$$ for three weak monobasic acids $$HA$$, $$HB$$ and $$HD$$ are $${ 10 }^{ -3 },{ 10 }^{ -7 }$$ and $${ 10 }^{ -9 }$$ ,respectively at $${ 25 }^{ o }C$$. Which of the following is correct prediction?
  • $${ (pH) }_{ NaA\ }>\ ({ pH) }_{ NaB }$$
  • $${ (pH) }_{ NaA }<\ ({ pH) }_{ NaB }$$
  • $${ (pH) }_{ NaA }> ({ pH) }_{ NaD }$$
  • $${ (pH) }_{ NaB }=7$$
$$2HI \rightleftharpoons H_2 + I_2$$
The equilibrium constant of the above reaction is $$6.4$$ at $$300$$ K. If $$0.25$$ mole each of $$H_2$$ and $$I_2$$ are added to the system, the equilibrium constant will be:
  • 1.6
  • 3.2
  • 0.8
  • 6.4
Strong electrolyte of the following is?
  • $$01M$$ $$HAc$$
  • $$0.1M$$ $$HCl$$
  • $$0.1M$$ $$KCl$$
  • $$0.1M$$ $$NaCl$$
Statement (A): For a liquid-vapour equilibrium the system must be a closed system.
Statement (B): For the equilibrium $${ H }_{ 2 }{ O }_{ \left( s \right)  }\rightleftharpoons { H }_{ 2 }{ O }_{ \left( 1 \right)  }$$, High temperature favours the formation of liquid
Statement (C): For the equilibrium $${ NH }_{ 4 }{ CI }_{ \left( s \right)  }\rightleftharpoons { NH }_{ 4 }{ CI }_{ \left( g \right)  }-x$$ K cal low temperature favours the formation of solid $${ NH }_{ 4 }CI$$
  • All the statements are correct
  • All the statements are incorrect
  • A, B are correct and C is incorrect
  • A, B are incorrect and C is correct
100 mL of 20.8% $$BaCl_2$$ solution and 50 mL of 9.8% $$H_2SO_4$$ solution will form $$BaSO_4$$
$$(Ba=137, Cl=35.5, S=32, H=1, O=16)$$
$$BaCl_2+H_2SO_4\rightarrow BaSO_4+2HCl$$
  • 23.3 g
  • 11.65 g
  • 30.6 g
  • None of these
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