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CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 15 - MCQExams.com

A buffer solution is 0.25MCH3COOH+0.15MCH3COONa, saturated in H2S(0.1M) and has [Mn2+]=0.04M, Ka(CH3COOH)=2.0×105, Ka(H2S)=1.0×1021 and Ksp(MnS)=2.5×1013.
Which buffer component should be increased in concentration and to which minimum value to just start precipitation of MnS?
  • CH3COOH,1.25M
  • CH3COONa,0.25M
  • CH3COONa,1.25M
  • CH3COONa,0.50M
An amount of 0.10 moles of AgCl(s) is added to one litre of water. Next, the crystals of NaBr are added until 75% of the AgCl is converted to AgBr(s), the less soluble silver halide. What is Br at this point? 

Ksp of AgCl=2×1010 and Ksp of AgBr=4×1013.
  • 0.075 M
  • 0.025 M
  • 1.5×104M
  • 0.027 M
What concentration of free CN must be maintained in a solution that is 1.8MAgNO3 and 0.16MNaCl to prevent AgCl from precipitating? Kf for Ag(CN)2=6.4×1017 and Ksp for AgCl=1.8×1010
  • 2.5×109M
  • 5×105M
  • 2.5×105M
  • 1×104M
When 20ml of 0.2MDCl solution is mixed with 80ml of 0.1MNaOD solution, pD of the resulting solution becomes 13.6. The ionic product of heavy water, D2O, is
  • 1015
  • 1016
  • 4×1015
  • 4×1016
An amount of 0.01 moles of solid AgCN is rendered soluble in 1l by adding just sufficient excess cyanide ion to form Ag(CN)2 and the concentration of free cyanide ion is 2.5×107M. Determine [Ag+] in the solution neglecting hydrolysis of cyanide ion. Kdiss for Ag(CN)2=1.0×1020.
  • 6.25×109M
  • 1.6×109M
  • 1.6×107M
  • 6.25×107M
A 40.0ml solution of weak base, BOH is titrated with 0.1NHCl solution. The pH of the solution is found to be 10.0 and 9.0 after adding 5.0ml and 20.0ml of the acid, respectively. The dissociation constant of the base is (log2=0.3)
  • 2×105
  • 1×105
  • 4×105
  • 5×105
Which of the following statement(s) is/are incorrect?
  • When water is added to KCN, a reaction occurs because the CN ion is a strong proton acceptor.
  • No reaction occurs when KCl is dissolved in water because neither K+ nor Cl can remove or accept proton from water.
  • When water is added to sodium acetate, an acidic solution is produced because of the formation of free acetic acid from the action of water on CH3COO.
  • (NH4)2CO3 smells strongly of NH3 because the strong base CO23 is able to remove protons from NH+4 ion.
Which of the following statements is/are correct?
  • A buffer solution may contain a weak acid and its conjugate base.
  • A buffer solution shows little change in pH on the addition of a small amount of acid or base.
  • A buffer solution can be prepared by mixing a solution of ammonium acetate and acetic acid.
  • The addition of solid potassium cyanide to water increases the pH of water.
The relation pKa=14pKb is true for which of the following pair(s)?
  • MeNH+3,CH3NH2
  • CH3COOH,CH3COO
  • H3O+,OH
  • Na+,NaOH
If K1 and K2 are the first and second ionization constants of H2CO3 and K1>>K2, the incorrect relation(s) is/are
  • [H+]=[HCO3]
  • [H+]=K1[HCO3]
  • K2=[CO23]
  • [H+]=2[CO23]
Which of the following may act as buffer in aqueous solution?
  • NH4Cl+NH4OH
  • CH3COOH+CH3COONa
  • CH3COONa+NaCl
  • Borax+Boricacid
The molar ratio of dimer to monomer for 0.1M acetic acid in benzene is equal to
  • 150:1
  • 1:150
  • 5:2
  • 2:5
Which of the following will occur if a 0.1M solution of a weak acid is diluted to 0.01M at constant temperature?
  • [H+] will decrease
  • pH will increase
  • Percentage ionization will increase
  • Ka will increase
Which of the following processes will increase [OH] in NH4OH solution?
  • Addition of HCl solution.
  • Addition of water.
  • Addition of NH4Cl solution.
  • Addition of solid NH4OH.
A volume of 500ml of 0.01MAgNO3 solution, 250ml of 0.02MNaCl solution and 250ml of 0.02MNaBr solution are mixed. The final concentration of bromide ion in the solution is (Ksp of AgCl and AgBr are 1010 and 5×1013, respectively.)
  • 0.01M
  • 0.02M
  • 0.005M
  • 2.5×105M
In the system, LaCI3(s)+H2O(g)+heatLaCIO(s)+2HCI(g), equilibrium is established. More water vapour is added to distributed the equilibrium . If the pressure of water vapour at new eqilibrium is double of that at initial equilibrium, the factor by which pressure of HCI is changed is
  • 2 times
  • 2times
  • 12times
  • 4 times
The amino acid alanine has two isomers, α alanine and β alanine when equal masses of these two compound are dissolved in equal mass of a solvent, the solution of α alanine freeze at relatively l; lower temperature, which forms α alanine and β alanine has the larger equilibrium constant for ionization?
  • α alanine
  • β alanine
  • same for both
  • unpredictable
The molar ratio of dimer to monomer for 0.1M acetic acid in water (neglecting the dissociation of acetic acid in water) is equal to
  • 250:1
  • 1:250
  • 9:2500
  • 2500:9
The initial rate of hydrolysis of methyl acetate (1.0M) by a weak acid (HA,1.0M) is 1/100th of that of a strong acid (HX,1.0M), at 25oC. The Ka of HA is
  • 1×104
  • 1×105
  • 1×106
  • 1×103
Single Correct Answer Type
The phenomenon in which white transparent crystal change into white is called:
  • Deliquescence
  • Efflorescence
  • Allotropy
  • Sublimation
The actual composition of nitrolim is :
  • Ca(CN)2
  • CaC2+Ca(CN)2
  • CaCN2+C
  • CaH2
Aqueous solution of HNO3,KOH,CH3COOH and CH3COONa of identical concentration are provided. The pair(s) of solution which forms buffer upon mixing is (are)
  • HNO3 and CH3COOH
  • KOH and CH3COONa
  • HNO3 and CH3COONa
  • CH3COOH and CH3COONa
Which one of the following salts given as acidic solution in water?
  • CH3COONa
  • NH4Cl
  • NaCl
  • CH3COONH4
The hydrogen ion concentration of a slightly acidic water solution can be represented by
  • 10pOH
  • 14pOH
  • KwpOH
  • 10(14pOH)
When NH_4Cl is added to NH_4OH solution, the dissociation of ammonium hydroxide is reduced. It is due to:
  • Common ion effect
  • Hydrolysis
  • Oxidation
  • Reduction
According to the reaction PbCl_2\rightarrow Pb^{2+} +2Cl^-, the solubility coefficient of PbCl_2 is:
  • [Pb^{2+}] [Cl^-]^2
  • [Pb^{2+}] [Cl^-]
  • [Pb^{2+}]^2 [Cl^-]
  • None\ of\ these
The concentration of KI and KCl in a certain solution containing both is 0.001\ M each. If 20\ ml of this solution is added to 20\ ml of a saturated solution of AgI in the water. What will happen?
(K_{sp}​AgCl=10^{−10};K_{sp}​AgI=10^{−16})
  • AgCl will be precipitated
  • AgI will be precipitated
  • Both AgCl and AgI will be precipitated
  • There will be no precipitated
Ionic product of water increase if________
  • Pressure is reduced
  • H^+ is added
  • OH^- is added
  • Temperature increases
The ionic of water at 25^oC is 10^{-14}. The ionic product at 90^oC will be:
  • 1\times 10^{-20}
  • 1\times 10^{-12}
  • 1\times 10^{-14}
  • 1\times 10^{-16}
Out of the following which pair of solutions is not a buffer solution?
  • NH_{4}Cl+NH_{4}OH
  • NaCl+NaOH
  • Na_{2}HPO_{4}+Na_{3}PO_{4}
  • CH_{3}COOH+CH_{3}COONa
K_{a1},K_{a2} and K_{a3} are the respective ionisation constants for the following reactions:
H_{2}S\leftrightharpoons H^{+}+HS^{-}
HS^{-}\leftrightharpoons H^{+}+S^{2-}
H_{2}S\leftrightharpoons 2H^{+}+S^{2-}
The correct relationship between K_{a1},K_{a2} and K_{a3} is,
  • K_{a3}=K_{a1}\times K_{a2}
  • K_{a3}=K_{a1}+K_{a2}
  • K_{a3}=K_{a1}-K_{a2}
  • K_{a3}=K_{a1}/K_{a2}
Which of the following salt is insoluble in water?
  • CuSO_{4}
  • CdSO_{4}
  • PbSO_{4}
  • Al_{2}(SO_{4})_{3}
Which of the following will nit function as a buffer solution
  • NaCl and NaOH
  • NaOH and NH_{4}OH
  • CH_{3}COONH_{4} and HCl
  • Borax and boric acid
Compound (F) is used as an artificial sweetner and is known as saccharin. It forms sodium salt. Which statement is correct about its sodium salt?
  • (F) has an acidic H atom and its conjugate base is delocalised to (C=O) group
  • (F) has an acidic H atom and its conjugate base is delocalised to ({SO}_{2}) group
  • Both statements (a) and (b) are correct
  • (F) does not have an acidic H atom
Which of the following pairs of ions would be expected to from precipitate when their dilute solution are mixed
  • Na^{+},SO^{2-}_{3}
  • NH^{+}_{4},CO^{2-}_{3}
  • Na^{+}, S^{2-}
  • Fe^{2+},PO^{3-}_{4}
In preparation of CHCl_3 from ethanol and bleaching powder , the latter provides
  • Ca(OH)_2
  • Cl_2
  • Both (a) and (b)
  • None of these
What will be the ionisation constant of formic acid if its 0.01 M solution is 14.5% ionised?
  • 2.1 \times 10^{-4}
  • 14.5
  • 0.145
  • 1.45 \times 10^{-4}
Match the column I with column II and mark the appropriate choice.
1842075_30701b32f03343e096d7258dbd98a419.PNG
  • (A) \rightarrow (i), (B) \rightarrow (iii), (C) \rightarrow (ii), (D) \rightarrow (iv)
  • (A) \rightarrow (ii), (B) \rightarrow (iv), (C) \rightarrow (iii), (D) \rightarrow (i)
  • (A) \rightarrow (iv), (B) \rightarrow (ii), (C) \rightarrow (i), (D) \rightarrow (iii)
  • (A) \rightarrow (iii), (B) \rightarrow (iv), (C) \rightarrow (ii), (D) \rightarrow (i)
The salt having the least solubility in water is :
  • BaCl_2
  • Ba(NO_3)_2
  • MgSO_4
  • BaSO_4
Among \mathrm{FeSO}_{4} .7 \mathrm{H}_{2} \mathrm{O}(\mathrm{A}), \mathrm{CuSO}_{4} .5 \mathrm{H}_{2} \mathrm{O}(\mathrm{B}) \mathrm{ZnSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}(\mathrm{C}), \mathrm{MnSO}_{4} \cdot 4 \mathrm{H}_{2} \mathrm{O}(\mathrm{D}), isomorphous salts are
  • \mathrm{A} and \mathrm{C}
  • A and D
  • C and B
  • A and B
Mark the appropriate choice to fill up the blanks in the given paragraph.
A solution which maintains constant pH when small amounts of a acid or base are added is known as a (i) A mixture of acetic acid and sodium acetate acts as (ii) with a pH around (iii) and a mixture of ammonium chloride and ammonium hydroxide acts as (iv) with a pH around (v)
Baking soda is a mixture of:
  • Sodium carbonate and acetic acid
  • Sodium carbonate and tartaric acid
  • Sodium hydrogen carbonate and tartaric acid
  • Sodium hydrogen carbonate and acetic acid
Which solutions are mixed to form a buffer solution ?
  • Strong acid and its salt with strong base
  • Strong acid and its salt with weak base
  • Weak acid and its salt with strong base
  • Weak acid and its salt with weak base
Which of the following is not a buffer ?
  • H_{2}CO_{3} / HCO_{3}^{-}
  • CH_{3}COOH / CH_{3}COONa
  • NH_{4}OH / NH_{4}Cl
  • NH_{4}OH / CH_{3}COOH.
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Practice Class 11 Medical Chemistry Quiz Questions and Answers