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CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 14 - MCQExams.com

At 90C, pure water has [H3O+]=106.7 mol/lit. What is the value of KW at 90C:
  • 106
  • 1012
  • 1014
  • 1013.4
Which of the following will not function as buffer solution?
  • NaH2PO4 + Na2HPO4(1:1MolarRatio)
  • NH4Cl + NaOH(2:1MolarRatio)
  • HCOOH + NaOH(1:1MolarRatio)
  • HCOOH + HCOONa(1:1MolarRatio)
In which of the following solution of electrolyte, ionic equilibrium is set up?
  • H2SO4
  • HCl
  • NaOH
  • HCN
Which of the following is a buffer solution? 
  • 500 mL of 0.1 N CH3COOH +500 mL of 0.4 N NaOH
  • 500 mL of 0.1 N CH3COOH +500 mL of 0.1 N HCl
  • 500 mL of 0.1 N CH3COOH +500 mL of 0.2 N NaOH
  • 500 mL of 0.1 N CH3COOH +500 mL of 0.3N NaOH
On adding NaCl solution to the saturated solution of PbCl2 then the concentration of :
  • Pb2+ will increase
  • Cl will decrease
  • Pb2+ will decrease
  • Ions will remain unaltered
The ionic product of water at 25oC is 1014 The ionic product at 90oC will be 
  • 1×1020
  • 1×1012
  • 1×1014
  • 1×1016
In a buffer solution the ratio of concentration of NH4ClandNH4OHis1:1 when it changes in 2:1 what will be the value of pH of buffer:-
  • Increase
  • Decrease
  • No effects
  • N. O. T.
A hydrogen electrode placed in a buffer solution of NaCl and HCN in the ratio of X:Y and Y:X has an oxidation electrode potential values E1andE2 volts respectively at 250C. The pKa value of HCN is
  • (E1+E2)0.118
  • (E1+E2)0.118
  • (E1E2)0.118
  • (E2E1)0.118
If the degree of ionization of water is 1.8 x 109 at a given temperature. Its ionic product will be 
  • 1.8 x 1016
  • 1 x 1014
  • 1 x 1016
  • 1.67 x 1014
2H2OH3O++OH,Kw=1×1014 at 25C hence Ka is :
  • 1×1014
  • 18×1017
  • 5.55×103
  • 1.00×107
The dissociation constant of a weak acid is 1.0×105, the equilibrium constant for its reaction with strong base is 
  • 1.0×105
  • 1.0×109
  • 1.0×107
  • 1.0×1014
One litre of water contains 107 mole of H+ ions. Degree of ionisation of water is:
  • 1.8×107%
  • 0.8×109%
  • 3.6×109%
  • 3.6×107%
Aqueous solution of NaCl is neutral because 
  • Na+ undergoes hydrolysis
  • Cl undergoes hydrolysis
  • Both Na+ and Cl undergo hydrolusis
  • Does not undergo hydrolysis
Which of the following may be regarded as buffer solution? 
  • 50 ml of 0.1 M acetic acid + 50 ml of 0.05 M NaOH
  • 50 ml of 0.05 ammonia + 50 ml of 0.1 M HCl
  • 25 ml of 0.1 M acetic acid + 50 ml of 0.1 M NaOH
  • 50 ml of 0.1 ammonia + 50 ml of 0.05 M HCl
The total number of different kind of buffer obtained during the titration of H3PO4 with NaOH are:- 
  • 3
  • 1
  • 2
  • 0
Select the correct acid-base equilibrium.
  • HNO3+HFH2NO+3+F
  • HNO3+HFH2F++NO3
  • CH3COOH+NH3CH3COOH+2+NH+2
  • HF+H2OH2F++OH
HCOOH and CH3COOH solutions have equal pH. If K1K2 (ratio of ionisation constants of acids) is 4, their molar concentration ratio will be:
  • 2
  • 0.5
  • 4
  • 0.25
At 90C, pure water has [H3O+]=106mol litre 1. The value of Kw at 90C is:
  • 106
  • 1012
  • 1014
  • 108
Hydrogen ion concentration of an aqueous solution is 1×104M. The solution is diluted with equal volume of water. Hydroxyl ion concentration of the resultant solution in terms of mol dm3 is __________.
  • 1×108
  • 1×106
  • 2×1010
  • 0.5×1010
If 1M C{H_3}COONa is added to 1M C{H_3}COOH, then:
  • pH of the solution increases
  • pH decreases
  • pH does not change
  • cannot be predicted
The dissociation constants for acetic acid  and HCN at 25^{0}C are 1 . 5 \times 10^{-5}  and 4 . 5 \times 10 ^{-10} , respectively. The equilibrium constant for the equilibrium CN^{-} + CH_{3}COOH \leftrightharpoons HCN + CH_{3}COO^{-} would be :
  • 3\times10^{4}
  • 3\times10^{5}
  • 3\times10^{-5}
  • 3\times10^{-4}
At { 25 }^{ \circ  }C the dissociation constant of a base , BOH, is 1.0\times { 10 }^{ -12 }. The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be
  • 1.0\times { 10 }^{ -6 }{ molL }^{ -1 }
  • 1.0\times { 10 }^{ -7 }{ molL }^{ -1 }
  • 2.0\times { 10 }^{ -6 }{ molL }^{ -1 }
  • 1.0\times { 10 }^{ -5 }{ molL }^{ -1 }
A solution is saturated with respect to AgSCN as well as AgBr. The concentration of Ag^{+} in the solution would be:
( K_{sp} for AgSCN = 1.2 \times 10^{-12} and for AgBr = 5 \times 10^{-13}
  • 1.3 \times 10^{-5}
  • 1.3 \times 10^{-12}
  • 1.3 \times 10^{-6}
  • 1.3 \times 10^{-8}
Which of the following salt evolve(s) { N }_{ 2 } gas on heating ?
  • \left( { NH }_{ 4 } \right) _{ { 2 } }{ CrO }_{ 4 }
  • { NH }_{ 4 }{ NO }_{ 2 }
  • { NH }_{ 4 }{ NO }_{ 3 }
  • \left( { NH }_{ 4 } \right) _{ { 2 } }{ CO }_{ 3 }
Which of following salt solution will impart greenish colour ?
  • K_2Cr_2O_7
  • ZnCl_2
  • K_2MnO_4
  • K_2CrO_4
10 ml of 0.2 M AgNO_3 is mixed with 10 ml of 0.1 M NaCl. What is the concenctration of Cl^- in the resulting solution [ K_{sp} (AgCl) = 10^{-10} M^2]
  • 10^{-5} M
  • 10^{-9} M
  • 2 \times 10^{-9} M
  • 10^{-8} M
For preparing a buffer solution of pH = 7.0, which buffer system you will choose?
  • H_3PO_4,H_2PO_4^-
  • H_2PO_4^-, HPO_4^{2-}
  • HPO^{2-}_4, PO^{3-}_4
  • H_3PO_4, PO_4^{3-}
The percentage of pyridine \left( { C }_{ 5 }{ H }_{ 5 }N \right) that forms pyridinium ion \left( { C }_{ 5 }{ H }_{ 5 }{ N }^{ + }H \right) in a 0.10 m aqueous pyridine solution \left( K_{ b } \ for\ { C }_{ 5 }{ H }_{ 5 }N=1.7\times { 10 }^{ -9 } \right) is:
  • 0.0060%
  • 0.013%
  • 0.77%
  • 1.6%
A weak acid react with strong base, ionisation constant of weak acid is { 10 }^{ -4 }. Find out equilibrium constant for this reaction. 
  • { 10 }^{ -10 }
  • { 10 }^{ 10 }
  • { 10 }^{ -9}
  • { 10 }^{ 9}
Which statement is/are correct-
  • If 0.1\ M CH_3COOH aqueous solution ( K_a = 1.8 \times 10^{-5} ) is diluted at 2560^o C , then [H^+] will increase
  • On heating a sample of pure water [H^+] and [OH^-] increases but the sample still remains neutral
  • 10^{-4}\ M HCl solution is less acidic than 0.1\ M HCN ( K_a HCN = 10^{-5} )
  • 10^{-8}\ M HCl aqueous solution will have pH exactly equal to 8
The self ionisation constant of \mathrm { NH } _ { 3 } at 50 ^ { \circ } \mathrm { C }  is given by \mathrm { K } _ { \mathrm { NH } _ { 3 } } = \left[ \mathrm { NH } _ { 4 } ^ { + } \right] \left[ \mathrm { NH } _ { 2 } ^ { - } \right] = 10 ^ { - 30 }. How many N H _ { 2 } ^ { - } ions are present per \mathrm { cm } ^ { 3 } of pure liquid \mathrm { NH } _ { 3 }?
  • 6 \times 10 ^ { 6 }
  • 6 \times 10 ^ { 5 }
  • 6 \times 10 ^ { - 5 }
  • 6 \times 10 ^ { - 6 }
The dissociation constant of an acid HA is 1 \times 10 ^ { - 5 }. The pH of 0.1 molar solution of the acid will be approximately:
  • 3
  • 5
  • 1
  • 6
The silicate anion in the mineral kinetic is a chain of three SiO_4^{4^-} tetrahedral that shares conners with adjacent tetrahedral. The mineral also contains Ca icon Cu ions and water molecules in a 1:1:1 ratio mineral represented as:
  • CaCu_2Si_{ 3 }O_{ 10 }.H_{ 2 }O
  • CaCuSi_{ 3 }O_{ 10 }.H_{ 2 }O
  • Ca_{ 2 }Cu_{ 2 }Si_{ 3 }O_{ 10 }.2H_{ 2 }O
  • None of these
Which of the following is ionic?
  • HCl
  • CHCl_3
  • IF_5
  • KI
For which salt the \mathrm { pH } of its solution does not change with dilution?
  • \mathrm { NH } _ { 4 } \mathrm { Cl }
  • \mathrm { CH } _ { 3 } \mathrm { COONH } _ { 4 }
  • \mathrm { CH } _ { 3 } \mathrm { COONa }
  • None of these
Consider the following equilibrium.
Liquid \rightleftharpoons Vapour
Which of the following relation is correct?
  • \dfrac{d ln P}{dT}=\dfrac{\Delta Hv}{RT^2}
  • \dfrac{d ln G}{dT^2}=\dfrac{\Delta Hv}{RT^2}
  • \dfrac{d ln P}{dT}=\dfrac{-\Delta Hv}{RT}
  • \dfrac{d ln P}{dT^2}=\dfrac{-\Delta Hv}{T^2}
The pH of an aqueous solution of sodium chloride at 60^{\circ}C is
  • 7.0
  • > 7.0
  • <7.0
  • 0
The EMF of cell: H_{2}(g)| Buffer \parallel Normal calmelelectrod, is 0.70 V at 25^{\circ}C, when barometric pressure is 760 mm. What is the pH of the buffer solution? E_{Calomel}^{0} = 0.28 V. [2.303 RTIF = 0.06]
  • 3.5
  • 7.0
  • tending to zero
  • tending to 14.0
The dissociation constant of formic acid is 0.00024. The hydrogen ion concentration in 0.002 M \ HCOOH solution is nearly
  • 6.93 \times 10^{-4}M
  • 4.8 \times 10^{-7}M
  • 5.8 \times 10^{-4}M
  • 1.4 \times 10^{-4}M
The degree of dissociation of pure water at 25^{\circ}C is found to be 1.8 \times 10^{-9}. The dissociation constant, K_{d} of water, at 25^{\circ}C is
  • 10^{-14}
  • 1.8 \times 10^{-16}
  • 5.56 \times 10^{-13}
  • 1.8 \times 10^{-14}
Which one of the following salts gives aqueous solution which is neutral?
  • NaHC{ O }_{ 3 }
  • NaHS{ O }_{ 4 }
  • NaCl
  • \\ Na{ H }_{ 4 }HC{ O }_{ 3 }
When ammonia is added to pure water, the concentration of which of the following species already present, will decrease?
  • OH^-
  • H_3O^+
  • NH_4^+
  • None of these
n-caproic acid, C_{5}H_{11}COOH, found in coconut and palm oil is used in making artificial flavors, has solubility in water equal to 11.6 g/L. The saturated solution has pH = 3.0. The K_{a } of acid is
  • 10^{-6}
  • 10^{-5}
  • 2 \times 10^{-5}
  • 2 \times 10^{-6}
What is [H^+] in mol/L of a solution that is 0.20 M CH_3CCONa and 0.10 M in CH_3COOH
( K_a\ for\ CH_3COOH = 1.8 \times 10^{-5} )  
  • 3.5 \times 10^{-4}
  • 1.1 \times 10^{-5}
  • 1.8 \times 10^{-5}
  • 9.0 \times 10^{-6}
A solution has initially 0.1 M -HCOOH and 0.2 M- HCN. K_{a} of HCOOH = 2.56 \times 10^{-4}, K_{a} of HCN = 9.6 \times 10^{-10}. The only incorrect statement for the solution is (log 2 = 0.3)
  • [H]^{+} = 1.6 \times 10^{-3} M
  • [HCOO]^{-} = 1.6 \times 10^{-3} M
  • [CN]^{-} = 1.2 \times 10^{-7} M
  • pOH = 2.8
Calculate the formation constant for the reaction of a tripositive metal ion with thiocyanate ions to form the monocomplex if the total metal concentration in the solution is 2 \times 10^{-3} M, the total SCN^{-} concentration is 1.51 \times 10^{-3} M and the free SCN^{-} concentration is 1.0 \times 10^{-5} M.
  • 7.55 \times 10^{4}
  • 3 \times 10^{5}
  • 3.33 \times 10^{-6}
  • 1.5 \times 10^{5}
Small amount of freshly precipitated magnesium hydroxides are stirred vigorously in a buffer solution containing 0.25 M of NH_{4}Cl and 0.05 M of NH_{4}OH. [Mg^{2+}] in the resulting solution is (K_{b} for NH_{4}OH = 2.0 \times 10^{-5} and K_{sp} of Mg(OH)_{2} = 8.0 \times 10^{-12})
  • 4 \times 10^{-6} M
  • 2 \times 10^{-6} M
  • 0.5 M
  • 2.0 M
A volume of 1.0 L of solution which was in equilibrium with solid mixture of AgCl and Ag_{2}CrO_{4} was found to contain 1 \times 10^{-4} moles of Ag^{+} ions, 1.0 \times 10^{-6} moles of CI^{-} ions and 8.0 \times 10^{-4} moles of CrO_{4}^{2-} ions. Ag^{+} ions are added slowly to the above mixture (keeping the volume constant) till 8.0 \times 10^{-7} moles of AgCl got precipitated. How many moles of Ag_{2}CrO_{4} were precipitated simultaneously?
  • 7.68 \times 10^{-4}
  • 4.8 \times 10^{-4}
  • 8.0 \times 10^{-4}
  • 7.68 \times 10^{-5}
Which one of the following is not an acid salt?
  • NaH_2PO_2
  • NaH_2PO_3
  • NaH_2PO_4
  • Na_2HPO_4
The solubility of AgCN in a buffer solution of pH - 3.0 is (K_{sp} of AgCN = 1.2 \times 10^{-16}; K_{a} of HCN = 4.8 \times 10^{-10})
  • 1.58 \times 10^{-5}M
  • 2.0 \times 10^{-5}M
  • 1.58 \times 10^{-4}M
  • 2.5 \times 10^{-9}M
0:0:2


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