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CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 9 - MCQExams.com

In order to prepare a buffer of pH=8.26, the amount of (NH4)2SO4 required to be mixed with one litre of 0.1(M)NH3(aq), pKb = 4.74 is:
  • 1.0 mole
  • 10.0 mole
  • 0.50 mole
  • 5 mole
In a buffer solution, the ratio of the concentration of NH4CI and NH4OH is 1 : 1 when it changes to 2 : 1, what will be the effect on pH of the buffer?
  • Increase
  • Decrease
  • No change
  • First increase then decrease
A buffer solution of pH = 5.15 is to be prepared from acetic acid (Ka = 
$$1.80x10^5$$ ), sodium acetate and water. What must be the molar ratio of acetate ion to acetic acid in this solution to obtain this pH?
  • 0.05mole
  • 2.54mole
  • 0.1mole
  • 0.005mole
The total number of different kind of buffers obtained during the titration of H3PO4  with NaOH are 
  • 3
  • 1
  • 2
  • 0
Each of the following forms a true solution in water. Which of them will allow the least etectric current to flow through it?
  • Alum
  • Table saIt
  • Cane sugar
  • Mohr's salt
Which of the following solutions display common ion effect?
  • HCl+NaCl
  • H2S+KH
  • NaHS+HCl
  • H2SO4+K2S
Which of the following is an example of weak electrolyte?
  • H3BO3
  • H2SO4
  • HNO3
  • HClO3
One liter of solution contains 105 moles of H+ ions at 25oC.Percentage ionisation of water in solution is:
  • 1.8×107%
  • 1.8×105%
  • 3.6×109%
  • 1.8×1011%
Dissolution of salt participate in water shows:
  • Particulate nature of matter.
  • Continuous nature of matter.
  • Particle size of salt is very big.
  • All of these.
If the first dissociation of X(OH)3 is 100% where as second dissociation is 50% and third dissociation is negligible then the pH of 4×103 MX(OH)3 is :
  • 11.78
  • 10.78
  • 2.5
  • 2.22

The pH of a solution which is 0.1 M in HA and 0.5 M in NaA. Ka for HA is 1.8×106 

  • 5.44
  • 6.44
  • 6.0
  • 4.73
 At 25oC, the dissociation constant for pure water is given by :-
  • (55.4×1014)1
  • 1×1014
  • 1×101418
  • none of these
The values of dissociation constants of some acids (at 250C) are as follows. Indicate which is the strongest acid in water?
  • 1.4×102
  • 1.6×104
  • 4.4×1010
  • 4.3×107
Ionic product of H2O is 1014. The H+ ion concentration in 0.1 M NaOH solution is:
  • 1011 M
  • 1013 M
  • 101 M
  • 104 M
Which among the following salts will give basic solution on hydrolysis?
  • NH4Cl
  • NaNO3
  • K2CO3
  • KCl
The mass of acetic acid present in 500 ml of solution in which it is 1% ionised (Ka of CH3COOH=1.8×105
  • 5.4 g
  • 12.6 g
  • 6.4 g
  • 10.8 g
The value of observed and calculate molecular weights of silver nitrate are 92.64 and 170 respectively. 

The degree of dissociation of silver nitrate will be :
  • 60%
  • 83.5%
  • 85.3%
  • 41.6%
When 0.1 mole of an acid is added to 2 lit of a buffer solution, the pH of the buffer decreases by 0.The buffer capacity of the solution is:
  • 0.6
  • 0.4
  • 0.2
  • 0.1
What is [NH+4] in a solution containing 0.02M NH3 (Kb=1.8×105) and 0.01M KOH?
  • 1.8×105
  • 9×106
  • 3.6×105
  • None of the above
A buffer solution can be prepared from a mixture of:
  • CH3COONa and HCl in 1:1 mole ratio
  • CH3COONa and CH3COOH in 1:1 mole ratio
  • CH3COONa and HCl in 1:2 mole ratio
  • NH4Cl and NaOH in 1:2 mole ratio
Which of the following has maximum pKa :-
  • CH2FCOOH
  • CH3ClCOOH
  • CH3COOH
  • HCOOH
The solubility of CaF2 (Ksp=5.3×109) in 0.1 M solution of NaF would be : (Assume no reaction of cation/anion) .
  • 5.3×1010 M
  • 5.3×108 M
  • 5.3×107 M
  • 5.3×1011 M
Four grams of NaOH solid are dissolved in just enough water to make 1 litre of solution. What is the[H+] of the solution?
  • 102 moles/litre
  • 101 moles/litre
  • 1012 moles/litre
  • 1013 moles/litre
Ka for HF is 3.5×104. Calculate Kb for the fluoride ion.
  • 3.5×104
  • 1.0×107
  • 2.9×1011
  • 1.0×1014
Salt which on heating produces a mixture of two gases is :
  • NaNO3
  • Bi(NO3)3
  • Pb(NO3)2
  • NH4NO3
If 0.1 M of a weak acid is taken and its percentage of the degree of ionization is 1.34%, then its ionization constant will be:
  • 0.8×104
  • 1.79×105
  • 0.182×104
  • 1×104
The unit of ionic product of water Kw are 
  • Mol1L1
  • Mol2L2
  • Mol2L1
  • Mol2L2
Oxidation number of Cl in CaOCl2 (bleaching powder) is:
  • zero, since it contains Cl2
  • 1, since it contains Cl
  • 1, since it contains ClO
  • +1 and 1 since it contains ClO and Cl
Solution of FeCl3 and H2O is :
  • Basic
  • Acidic
  • Neutral
  • None of these
The number of H+ ions in 1 cc of a solution of pH=13 is:
  • 6.023×107
  • 1×1013
  • 6.023×1013
  • 1×1016
The concentration of [H+] and concentration of [OH+] of a 0.1M aqueous solution of 2%  ionised weak acid is [ionic product of water =1×1014]
  • 2×103M and 5×1012M
  • 1×103M and 3×1011M
  • 0.02×103M and 5×1011M
  • 3×102M and 4×1013M
Dissociation constant of 0.002M acotic add collection having conduct of 8×105scm1 & A˚ 400 s cm^2 mole^{-1} is 
  • 1.7 \times 10^{-4}
  • 2.1 \times 184
  • 2.9 \times 10^{-4}
  • 1.7 \times 10^{-3}
Addition of sodium acetate solution to acetic acid causes the following change-
  • pH increases
  • pH decreases
  • pH remains unchanged
  • pH becomes 7
Which pair can not act as buffer?
  • CH_3COOH + CH_3COONa
  • Borax + H_3BO_3
  • HCl + NH_4OH
  • NH_4Cl + HCl
The common ion effects is shown by which of the following sets of solutions:-
  • BaCl_{2}+Ba(NO_{3})_{2}
  • NaCl+HCl
  • NH_{4}OH+NH_{4}Cl
  • None
Electrolytic conduction is due to the movement of 
  • molecules
  • atoms
  • ions
  • electrons
Chlorides are mineral salts, and cannot be affected by
  • Chemical Actions
  • Biological Action
  • Temperature
  • Turbidity
What [H^+] must be maintained in a saturated solution to ppt. Pb^{+2} but not Zn^{+2} from a solution in which each ion is present at a concentration of 0.01\ M
Given, K_{sp} for H_2S=1.1\times 10^{-22}, K_{sp} for ZnS=10^{-21}.
  • 3.3\times 10^{-4}
  • 3.3\times 10^{-2}
  • 6.6\times 10^{-2}
  • 6.6\times 10^{-4}
Which of the following reacts with water?
  • CHCl_{3}
  • CCl_{4}
  • CCl_{3}CHO
  • CH_{2}ClCH_{2}Cl
C+O_{2}\rightarrow CO_{2} +Heat
  • Combination reaction
  • Decomposition reaction
  • Both (1) and (2)
  • none of these
Which of the following salts is insoluble in water at room temperature but soluble in boiling water?
  • CaCl_2
  • BaCl_2
  • SrCl_2
  • PbCl_2
Two elements have electronegativity of 1.2 and 3.Bond formed between them would be ________________.
  • predominantely ionic
  • predominantely covalent
  • co-ordinate bond
  • metallic bond
Basic strength of NH_{4}OH   in presence of NH_{4}CI  
  • Increase
  • Remains unchanged
  • Decreases
  • Some times increases or sometimes decrease
The pH of rain water is approximately_____.
  • 6.5
  • 7.5
  • 5.6
  • 7.0
Solubility of MX_{ 2 } type electrolytes is 0.5\times 10^{ -4 } mol/L, then find out { K }_{ sp } of electrolytes.
  • 5\times 10^{ -12 }
  • 25\times 10^{ -10 }
  • 1\times 10^{ -13 }
  • 5\times 10^{ -13 }
Hydrated cobalt(II) chloride decomposes on heating.
The equation for the reaction is
CoCl_{2}.6H_{2}O CoCl_{2} + 6H_{2}O
The reaction is reversed by adding water.
Which row describes the colour change and the type of reaction for the reverse reaction?
  • Colour change - blue to pink, type of reaction - endothermic
  • Colour change - blue to pink, type of reaction - exothermic
  • Colour change - pink to blue, type of reaction - endothermic
  • Colour change - pink to blue, type of reaction - exothermic
The number of hydronium ions in 1 ml of an aqueous solution of pH 12.0 at 25^{\circ}C is
  • 0.01
  • 10^{-12}
  • 6.02 \times 10^{8}
  • 6.02 \times 10^{11}
Predict the direction in which the following equilibrium will shift backward.
\underset{(g)}{N_2} + \underset{(g)}{3H_2} \Leftrightarrow \underset{(g)}{2NH_3 \,\, \Delta H} = -100 \, Joule
  • increasing Temperature
  • increasing pressure
  • addition of catalyst
  • on addition of NH_{3}
Which of the following pair will show common ion effect?
  • HCN +KOH
  • HBr +AgBr
  • HCOOH + CH_3COOH
  • KOH +AgOH
At 90^oC the concentration of H_3O^+ in pure water is 10^{-4} mol. Lit^- . What is the value of K_W at this temperature ?
  • 10^{-6}
  • 10^{-8}
  • 10^{-14}
  • 10^{-12}
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