CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 3 - MCQExams.com

If degree of ionization $$(\alpha )$$ of a weak electrolyte $$AB$$ is very less, then $$\alpha$$  is
  • directly proportional to the square root of volume of solution
  • inversely proportional to the dilution
  • inversely proportional to the square root of concentration
  • directly proportional to concentration
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
The solubility of $$CaF_{2}(K_{sp} = 3.4 \times 10^{-11})$$ in 0.1M solution of NaF would be:
  • $$3.4 \times 10^{-12}M$$
  • $$3.4 \times 10^{-10}M$$
  • $$3.4 \times 10^{-9}M$$
  • $$3.4 \times 10^{-13}M$$
$$NH_{4}OH$$  is weak base but it becomes still weaker in the aqueous solution of :
  • 0.1 M HCl
  • 0.1 M $$NH_{4} Cl$$
  • 0.1 M $$H_{2}SO_{4}$$
  • 0.1 M $$CH_{3}COOH$$
Which of the following mixture is not a buffer solution?
  • 100ml of 0.5 $$N - CH_{3}COOH +$$ 100 ml of 0.05 N- NaOH
  • 100ml of 0.5 $$N-NH_{4}OH +$$ 100ml of 0.5 N-HCl
  • 100 ml of 0.5 $$N-NH_{4}OH +$$ 10 ml of 0.5 $$N-H_{2}SO_{4}.$$
  • 300 ml of 0.5 $$N-NH_{4}OH +$$ 200 ml of 0.5 $$N-HNO_{3}$$
Match List-1 with List-2.
List -1                                                               List-2
A) $$CH_{3}COONa + CH_{3}COOH$$     1)Acidic due to cationic hydrolysis 
B) $$NH_{4}Cl + NH_{4}OH$$                     2)Basic due to anionic hydrolysis
C) aqueous $$AlCl_{3}$$                              3) Basic buffer solution
D) aqueous $$Na_{2}CO_{3}$$                         4)Acidic buffer solution
  • A - 1 ; B - 2 ; C - 3 ; D - 4
  • A - 4 ; B - 3 ; C - 1 ; D - 2
  • A - 2 ; B - 3 ; C - 1 ; D - 4
  • A - 4 ; B - 3 ; C - 2 ; D - 1
The $$K_{sp}$$ for AgCl is $$2.8\times 10^{-10}$$ at a given temperature. The solubility of AgCl in 0.01 molar HCl solution at this temperature will be :
  • $$2.8\times 10^{-12}mol L^{-1}$$
  • $$2.8\times 10^{-8}mol L^{-1}$$
  • $$5.6\times 10^{-8}mol L^{-1}$$
  • $$2.8\times 10^{-4}mol L^{-1}$$
A $$0.004 $$ M solution of $$Na_{2}SO_{4}$$ is isotonic with a $$0.010$$ M solution of glucose at same temperature. The apparent degree of dissociation of $$Na_{2}SO_{4}$$ is:
  • $$25$$%
  • $$50$$%
  • $$75$$%
  • $$85$$%
Which of the following mixture will act as buffer?
  • $$H_{2}CO_{3}+NaOH ( 3 : 2 mole ratio)$$
  • $$H_{2}CO_{3}+NaOH ( 3 : 4 mole ratio)$$
  • $$NH_{4}OH +HCl ( 5 : 4 mole ratio)$$
  • $$NH_{4}OH +HCl ( 4 : 5 mole ratio)$$
Which of the following statements is/are correct about the ionic product of water?
  • K (equilibrium constant of water) < K$$_{w}$$
  • pK>pK$$_{w}$$
  • At $$100^{0}C$$ $$Kw = 7.5 \times10^{-14}$$ $$(moles/lit)^{2}$$
  • Ionic product of water at $$25^{0}C is 10^{-14}$$
Assertion: A mixture of $$CH_3COOH$$ and $$CH_3COONH_4$$ is not a buffer solution.
Reason: An acidic buffer contains the mixture of a weak acid and its salt with a strong base.
  • Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
  • Assertion is correct but Reason is not correct
  • Assertion is not correct but Reason is correct
  • Both Assertion and Reason are not correct
Bleaching powder is used :
  • for bleaching cotton, wood pulp
  • as a disinfectant and germicide
  • for the manufacture of chloroform
  • as a reducing agent in industries
Assertion: pH of blood does not change in spite of taking acidic foods.
Reason: Blood behaves as a buffer solution.
  • Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
  • Assertion is correct but Reason is not correct
  • Assertion is not correct but Reason is correct
  • Both Assertion and Reason are not correct
What is the $$[OH^-]$$ in the final solution prepared by mixing $$20.0\ mL$$ of $$0.050\ M$$ $$HCl$$ with $$30.0\; mL$$ of $$0.10 \;M\; Ba(OH)_2$$?
  • $$0.12\ M$$
  • $$0.10\ M$$
  • $$0.40\ M$$
  • $$0.0050\ M$$

The degree of dissociation of an electrolyte depends on:
  • nature of the electrolyte
  • nature of solvent
  • temperature
  • all the above
Assertion: 
The pH of the buffer solution does not change when an acid or a base is added.

Reason: 
Buffer solution consists of a mixture of a weak acid and its salt with a strong base.
  • Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
  • Assertion is correct but Reason is not correct
  • Assertion is not correct but Reason is correct
  • Both Assertion and Reason are not correct

The degree of dissociation of an electrolyte does not depend on:
  • nature of electrolyte
  • catalytic action
  • dilution
  • temperature
Assertion: A buffer solution has a capacity to resist the change in pH value on an addition of a small amount of acid or base to it.
Reason: An aqueous solution of ammonium acetate can act as buffer.
  • Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
  • Assertion is correct but Reason is not correct
  • Assertion is not correct but Reason is correct
  • Both Assertion and Reason are not correct
Buffer solution has the capacity to restore the pH of a solution if some minor changes occur in $$H^+$$ concentration.
  • True
  • False
100ml of a buffer of $$1M NH_3(aq)\: and\: {1M NH_{4}}^{+}(aq)$$ are placed in two half cells separately. A current of 1.5amp is passed through both half cells for 20min, if electrolysis of only water take place. The pH of :
  • Anode half cell will decrease
  • Cathode half cell will decrease
  • Both half cell will decrease
  • Both half cell remain same
What is the term for the positive and negative ions of a compound breaking apart in solution?
  • Conglomeration
  • Oxidation
  • Dissociation
  • None of the above
A basic buffer consists of a mixture of weak base and its salt with weak acid.
  • True
  • False
Which of the following are present in a dilute aqueous solution of $$HCl$$?
  • $$H_{3}O^{+}+Cl^{-}$$
  • $$H_{3}O^{+}+OH^{-}$$
  • $$Cl^{-}+OH^{-}$$
  • Unionised $$HCl$$
Which one of the following can be used as an acid-base indicator by a visually impaired student?
  • Litmus
  • Turmeric
  • Vanilla essence
  • Petunia leaves
Mineral acids are stronger acids than carboxylic acids because :
(i) mineral acids are completely ionized.
(ii) carboxylic acids are completely ionized.
(iii) mineral acids are partially ionized.
(iv) carboxylic acids are partially ionized.
  • (i) and (iv)
  • (ii) and (iii)
  • (i) and (ii)
  • (iii) and (iv)
The minimum concentration of $$Ag^{+}$$ ion at which precipitation of at least one anion starts is:
  • $$10^{-8}$$.
  • $$1.41 \times$$ $$10^{-6}$$.
  • $$2 \times$$ $$10^{-6}$$.
  • $$2 \times$$ $$10^{-10}$$.
Which is not a buffer solution:
  • $$NH_{4}Cl+NH_{4}OH$$
  • $$CH_{3}COOH+CH_{3}COONa$$
  • $$CH_{3}COONH_{4}$$
  • $$NH_{4}NO_{3}$$
In a sample of pure water, which one of the following statements is always true at all conditions of temperature and pressure.
  • $$[OH^-] = 1.0\times10^{-14} M $$
  • $$[H_3O^+] = 1.0\times10^{-7} M $$
  • $$[OH^-] = 1.0\times10^{-7} M $$
  • $$[H_3O^+]=[OH^-]$$
The pH value of blood does not appreciably change by a small addition of an acid or a base, because the blood
  • is a body fluid
  • can be easily coagulated
  • contains iron as a part of the molecule
  • contains serum protein which acts as buffer
About buffer solution which is correct ?
  • It contains a weak acid and its conjugate base
  • It contains a weak base and its conjugate acid
  • It shows change in pH on adding small amount of acid or base
  • All of the above
The salt which does not react with acid or base is :
  • sodium hydroxide
  • sulphuric acid
  • sodium chloride
  • sodium acetate
Which of the following pairs constitutes a buffer?
  • $$NaOH and NaCl$$
  • $$HNO_{3} and NH_{4}NO_{3}$$
  • $$CH_{3}COOH+CH_{3}COONa$$
  • $$HNO_{2} and NaNO_{2}$$
The degree of dissociation of weak electrolyte increases by :
  • increasing the concentration of weak electrolyte solution
  • adding a common ion
  • dissolution in solvent of low dielectric constant
  • adding more amount of solvent into the solution
Le- Chatelier's  principle is applicable to both homogeneous and heterogeneous equilibria.
  • True
  • False
In which of the following salts, cation does not undergo hydrolysis but anion undergoes hydrolysis?
  • $$BaCO_{3}$$
  • $$CaCl_{2}$$
  • $$K_{2}CO_{3}$$
  • $$NaNO_{3}$$
The unit of $$K_w$$ is:
  • $$mol^2/L^2$$
  • $$mol/L^2$$
  • $$mol^2/L$$
  • $$mol/L$$
Which of the following combinations will make a buffer solution? 
(i) $$CH_3COONa\ (2 mol) + HCl\ (1 mol) $$
(ii) $$CH_3COOH\ (2 mol) + NaOH\ (1 mol) $$
(iii)$$ CH_3COOH\ (1 mol) + CH_3COONa\ (1 mol) $$
  • $$(iii) $$
  • $$(i), (ii)$$
  • $$(ii), (iii)$$
  • $$(i), (ii), (iii) $$
Identify the common property for a chemical reaction at dynamic equilibrium.
  • The measurable properties like concentration, density, colour, pressure etc remain constant at constant temperature.
  • The forward and backward reactions take place with the same rate.
  • It can be achieved from both directions.
  • All the above
Identity the false statements regarding ionic product of water:
  • ionic product of water increases on the addition of acids
  • ionic product of water is constant at a constant temperature
  • ionic product of water at $$0^{o}$$C can have a value of $$10^{-11}$$
  • neutral pH depends on the value of ionic product of water
What is meant by ionic product of water?
  • Concentrations of $$H^+$$ ions
  • Concentrations of $$OH^-$$ ions
  • The product of concentrations of $$H^+$$ and $$OH^-$$ ions
  • None of these
In the reaction : $$NO_2+CO \leftrightharpoons  NO+ CO_2$$, the equilibrium state may be recognized by the constancy of color.
  • True
  • False
State True or False.
$$S^{2-}$$ is the conjugate base of $$HS^-$$.
  • True
  • False
The $$pH$$ of blood is:
  • strongly acidic
  • neutral
  • strongly basic
  • slightly basic
The degree of dissociation of water in a 0.1M aqueous solution of HCl at a certain temperature $$t\ ^oC$$ is $$3.6\times 10^{-15}$$. The temperature $$t$$ must be:
[density of water at $$t\ ^oC=1 gm/ml]$$
  • $$< 25^oC$$
  • $$=25^oC$$
  • $$> 25^oC$$
  • Insufficient data to predict
Milk of magnesia used as a medicine for treating indigestion is a substance that -
  • Helps in disintegration of food products leading to their facile metabolism.
  • Combines with gastric hydrochloric acid thereby enhancing the latter's efficiency
  • Improves the enzymatic activities inside the stomach.
  • Neutralises excess acidity, providing a buffered medium inside the stomach.
A compound which is called microcosmic salt is:
  • $$Na_{2}HPO_{4}.2H_{2}O$$
  • $$NaH_{2}PO_{4}.H_{2}O$$
  • $$Na(NH_{4})HPO_{4}.4H_{2}O$$
  • $$Na_{2}(NH_{4})PO_{4}.2H_{2}O$$
Superphosphate of lime mainly acts as :
  • fungicide
  • disinfectant
  • fertiliser
  • all of the above
Which among the following factors changes the value of ionic product of water?
  • Change in temperature
  • Addition of acid
  • Addition of base
  • Addition of either acid and base.
$$pK_a$$ for the acid $$HA$$ is $$6$$. The value of $$K$$ for the reaction $$A^-+H_3O^+\rightleftharpoons HA+H_2O$$ is:
  • $$1\times 10^{-6}$$
  • $$1\times 10^{8}$$
  • $$1\times 10^{-8}$$
  • $$1\times 10^6$$
Which of the following salts can produce only two types of radicals?
  • $$NaKCO_3$$
  • $$CaOCl_2$$
  • $$NH_4HSO_4$$
  • $$Na(NH_4)HPO_4$$
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