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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 H2O
  • a stronger base than when it is dissolved in H2O
Calculate the OH concentration and the H3PO4 concentration of a solution prepared by dissolving 0.1 mol of Na3PO4 in sufficient water to make 1L of solution.
K1=7.1×103, K2=6.3×108; K3=4.5×1013
  • [OH]=1.36×102M, [H3PO4]=2.96×1018M
  • [OH]=3.73×102M, [H3PO4]=5.93×1018M
  • [OH]=5.9×102M, [H3PO4]=6.45×1018M
  • [OH]=6.45×102M, [H3PO4]=5.9×1018M
A solution contains HCl, Cl2HCCOOH and CH3COOH at concentrations 0.09M in HCl, 0.09M in Cl2HCCOOH and 0.1M in CH3COOH, pH for the solution is 1. Ionization constant of CH3COOH=105. What is the magnitude of K for dichloroacetic acid?
  • ka2=1.25×102
  • ka2=1.25×101
  • ka2=1.25×104
  • ka2=1.25×103
At 60oC, pure water has [H3O+]=106.7mol/lit.What is the value of KW at 60oC :-
  • 106
  • 1012
  • 1067
  • 1013.4
At 90oC, pure water [H3O] as 106molL1 what is the value of Kw at 90oC ?
  • 106
  • 1012
  • 1014
  • 108
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 HgI2 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 1.0×108M HCl is less than 7
  • The ionic product of water at 250C is 1.0×1014 mol2L2
  • Cl is a Lewis acid
  • Bronsted-Lowry theory cannot explain the acidic character of AlCl3
BaCl2 dissociates in water to give one Ba2+ ion and two Cl ions. If concentrated HCl is added to this solution :
  • [Ba2+] increases
  • [Ba2+] remains constant
  • [OH] increases
  • The number of moles of undissociated BaCl2 increases
  • [H+] 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.
  • KNO3(Δ=35.4 kJ mol1)
  • NaCl(Δ=5.35 kJ mol1)
  • HBr(Δ=83.3 kJ mol1)
  • KOH(Δ=55.6 kJ mol1)
At 298 K 0.01M NH4OH solution is 4.3% ionised.The ionization constant of NH4OH is :
  • 1.84×105
  • 2.05×105
  • 1.62×104
  • 1.84×104
Which of the following symbol represents acid dissociation constant?
  • pH
  • pOH
  • Ka
  • Kb
  • Kw
Which of the following will form a buffer solution of 1L solution?
  • 0.2 mol of HCl and 0.1 mole of K2SO3
  • 0.2 mol of NaOH and 0.4 mol of HF
  • 0.1 mol of HBr and 0.1 mol of Ba(OH)2
  • 0.4 mol of HCl and 0.2 mol of NH3
  • 0.2 mol of NaOH and 0.4 mol of 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?
  • H2O, 1 M NaOH, 1 M H2SO4
  • H2O,  1 M CH3COOH, 1 M Na+CH3COO
  • H2O, 1 M CH3COOH, 6 M Na+CH3COO
  • H2O, 1 M CH3COOH, 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 (C)Solubility in 100 g water
12044
23058
34067
45062
56084
Which trial seems to be in error?
  • 1
  • 2
  • 3
  • 4
  • 5
The Ksp for Mg(OH)2 in water is 1.2×1011. In an acidic solution, if the Mg2+ concentration is 1.2×105mol/L, what is the pH at which Mg(OH)2 just begins to precipitate?
  • 3
  • 4
  • 5
  • 11
  • 12
At 298K, KW of water is : 
  • 1×1014
  • 1×1017
  • 1×101
  • 1×107
Assertion: Water makes a good buffer.
Reason: A good buffer will resist changes in 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: Ag+(aq)+Cl(aq)AgCl(s). 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]=1.0M and [NaA]=1.0M. To (10+x)mL of this buffer solution 9mL of 1.0MHCl is added so that pH changes by one unit. The value of x is
  • 0.1
  • 10
  • 1.5
  • 1.0
MgCl2 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)
Ksp[Fe(OH)2]=7.9×1015 and Ksp[Cu(OH)2]=1.6×1019
  • 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.
pKb of NH3 is 4.74 and pKb of A,B and C are 4,5 and 6 respectively. Aqueous solution of 0.01 M has pH in the increasing order.
  • NH4A<NH4B<NH4C
  • NH4C<NH4B<NH4A
  • NH4C<NH4A<NH4B
  • 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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