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

At 90∘C, pure water has [H3O+]=10−6.7 mol/lit. What is the value of KW at 90∘C:−
  • 10−6
  • 10−12
  • 10−14
  • 10−13.4
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 10−14 The ionic product at 90oC will be 
  • 1×10−20
  • 1×10−12
  • 1×10−14
  • 1×10−16
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
  • (E1−E2)0.118
  • (E2−E1)0.118
If the degree of ionization of water is 1.8 x 10−9 at a given temperature. Its ionic product will be 
  • 1.8 x 10−16
  • 1 x 10−14
  • 1 x 10−16
  • 1.67 x 10−14
2H2O⇋H3O++OH−,Kw=1×10−14 at 25∘C hence Ka is :
  • 1×10−14
  • 18×10−17
  • 5.55×10−3
  • 1.00×10−7
The dissociation constant of a weak acid is 1.0×10−5, the equilibrium constant for its reaction with strong base is 
  • 1.0×10−5
  • 1.0×109
  • 1.0×107
  • 1.0×1014
One litre of water contains 10−7 mole of H+ ions. Degree of ionisation of water is:
  • 1.8×10−7%
  • 0.8×10−9%
  • 3.6×10−9%
  • 3.6×10−7%
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+HF⇌H2NO+3+F−
  • HNO3+HF⇌H2F++NO−3
  • CH3COOH+NH3⇌CH3COOH+2+NH+2
  • HF+H2O⇌H2F++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 90∘C, pure water has [H3O+]=10−6mol litre −1. The value of Kw at 90∘C is:
  • 10−6
  • 10−12
  • 10−14
  • 10−8
Hydrogen ion concentration of an aqueous solution is 1×10−4M. The solution is diluted with equal volume of water. Hydroxyl ion concentration of the resultant solution in terms of mol dm−3 is __________.
  • 1×10−8
  • 1×10−6
  • 2×10−10
  • 0.5×10−10
If 1M CH3COONa is added to 1M CH3COOH, then:
  • pH of the solution increases
  • pH decreases
  • pH does not change
  • cannot be predicted
The dissociation constants for acetic acid  and HCN at 250C are 1.5×10−5  and 4.5×10−10, respectively. The equilibrium constant for the equilibrium CN−+CH3COOH⇋HCN+CH3COO− would be :
  • 3×104
  • 3×105
  • 3×10−5
  • 3×10−4
At 25∘C the dissociation constant of a base , BOH, is 1.0×10−12. The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be
  • 1.0×10−6molL−1
  • 1.0×10−7molL−1
  • 2.0×10−6molL−1
  • 1.0×10−5molL−1
A solution is saturated with respect to AgSCN as well as AgBr. The concentration of Ag+ in the solution would be:
(Ksp for AgSCN=1.2×10−12 and for AgBr=5×10−13) 
  • 1.3×10−5
  • 1.3×10−12
  • 1.3×10−6
  • 1.3×10−8
Which of the following salt evolve(s) N2 gas on heating ?
  • (NH4)2CrO4
  • NH4NO2
  • NH4NO3
  • (NH4)2CO3
Which of following salt solution will impart greenish colour ?
  • K2Cr2O7
  • ZnCl2
  • K2MnO4
  • K2CrO4
10 ml of 0.2 M AgNO3 is mixed with 10 ml of 0.1 M NaCl. What is the concenctration of Cl− in the resulting solution [Ksp(AgCl)=10−10M2]
  • 10−5M
  • 10−9M
  • 2×10−9M
  • 10−8M
For preparing a buffer solution of pH = 7.0, which buffer system you will choose?
  • H3PO4,H2PO−4
  • H2PO−4,HPO2−4
  • HPO2−4,PO3−4
  • H3PO4,PO3−4
The percentage of pyridine (C5H5N) that forms pyridinium ion (C5H5N+H) in a 0.10 m aqueous pyridine solution (Kb for C5H5N=1.7×10−9) 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
  • 1010
  • 10−9
  • 109
Which statement is/are correct-
  • If 0.1 M CH3COOH aqueous solution (Ka=1.8×10−5) is diluted at 2560oC, 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 (KaHCN=10−5)
  • 10−8 M HCl aqueous solution will have pH exactly equal to 8
The self ionisation constant of NH3 at 50∘C  is given by KNH3=[NH+4][NH−2]=10−30. How many NH−2 ions are present per cm3 of pure liquid NH3?
  • 6×106
  • 6×105
  • 6×10−5
  • 6×10−6
The dissociation constant of an acid HA is 1×10−5. 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 SiO4−4 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:
  • CaCu2Si3O10.H2O
  • CaCuSi3O10.H2O
  • Ca2Cu2Si3O10.2H2O
  • None of these
Which of the following is ionic?
  • HCl
  • CHCl3
  • IF5
  • KI
For which salt the pH of its solution does not change with dilution?
  • NH4Cl
  • CH3COONH4
  • CH3COONa
  • None of these
Consider the following equilibrium.
Liquid ⇌ Vapour
Which of the following relation is correct?
  • dlnPdT=ΔHvRT2
  • dlnGdT2=ΔHvRT2
  • dlnPdT=−ΔHvRT
  • dlnPdT2=−ΔHvT2
The pH of an aqueous solution of sodium chloride at 60∘C is
  • 7.0
  • >7.0
  • <7.0
  • 0
The EMF of cell: H2(g)| Buffer ∥ Normal calmelelectrod, is 0.70 V at 25∘C, when barometric pressure is 760 mm. What is the pH of the buffer solution? E0Calomel=0.28V.[2.303RTIF=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 0.002M HCOOH solution is nearly
  • 6.93×10−4M
  • 4.8×10−7M
  • 5.8×10−4M
  • 1.4×10−4M
The degree of dissociation of pure water at 25∘C is found to be 1.8×10−9. The dissociation constant, Kd of water, at 25∘C is
  • 10−14
  • 1.8×10−16
  • 5.56×10−13
  • 1.8×10−14
Which one of the following salts gives aqueous solution which is neutral?
  • NaHCO3
  • NaHSO4
  • NaCl
  • NaH4HCO3
When ammonia is added to pure water, the concentration of which of the following species already present, will decrease?
  • OH−
  • H3O+
  • NH+4
  • None of these
n-caproic acid, C5H11COOH, found in coconut and palm oil is used in making artificial flavors, has solubility in water equal to 11.6g/L. The saturated solution has pH=3.0. The Ka of acid is
  • 10−6
  • 10−5
  • 2×10−5
  • 2×10−6
What is [H+] in mol/L of a solution that is 0.20 M CH3CCONa and 0.10 M in CH3COOH? 
(Ka for CH3COOH=1.8×10−5) 
  • 3.5×10−4
  • 1.1×10−5
  • 1.8×10−5
  • 9.0×10−6
A solution has initially 0.1M−HCOOH and 0.2M−HCN. Ka of HCOOH=2.56×10−4, Ka of HCN=9.6×10−10. The only incorrect statement for the solution is (log2=0.3)
  • [H]+=1.6×10−3M
  • [HCOO]−=1.6×10−3M
  • [CN]−=1.2×10−7M
  • 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 2×10−3M, the total SCN− concentration is 1.51×10−3M and the free SCN− concentration is 1.0×10−5M.
  • 7.55×104
  • 3×105
  • 3.33×10−6
  • 1.5×105
Small amount of freshly precipitated magnesium hydroxides are stirred vigorously in a buffer solution containing 0.25M of NH4Cl and 0.05M of NH4OH. [Mg2+] in the resulting solution is (Kb for NH4OH=2.0×10−5 and Ksp of Mg(OH)2=8.0×10−12)
  • 4×10−6M
  • 2×10−6M
  • 0.5M
  • 2.0M
A volume of 1.0L of solution which was in equilibrium with solid mixture of AgCl and Ag2CrO4 was found to contain 1×10−4 moles of Ag+ ions, 1.0×10−6 moles of CI− ions and 8.0×10−4 moles of CrO2−4 ions. Ag+ ions are added slowly to the above mixture (keeping the volume constant) till 8.0×10−7 moles of AgCl got precipitated. How many moles of Ag2CrO4 were precipitated simultaneously?
  • 7.68×10−4
  • 4.8×10−4
  • 8.0×10−4
  • 7.68×10−5
Which one of the following is not an acid salt?
  • NaH2PO2
  • NaH2PO3
  • NaH2PO4
  • Na2HPO4
The solubility of AgCN in a buffer solution of pH−3.0 is (Ksp of AgCN=1.2×10−16; Ka of HCN=4.8×10−10)
  • 1.58×10−5M
  • 2.0×10−5M
  • 1.58×10−4M
  • 2.5×10−9M
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