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 $$(NH_4)_2 SO_4$$ required to be mixed with one litre of $$0.1 (M) NH_3 (aq), $$ $$pK_b $$ = $$4.74 $$ is:
  • $$1.0\ mole $$
  • $$10.0\ mole $$
  • $$ 0.50 \ mole $$
  • $$ 5\ mole $$
In a buffer solution, the ratio of the concentration of $$NH_4CI$$ and $$NH_4OH$$ 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?
  • $$0.05 mole$$
  • $$2.54 mole$$
  • $$0.1 mole$$
  • $$0.005 mole$$
The total number of different kind of buffers obtained during the titration of $$H_{3}PO_{4}$$  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?
  • $$HCl+NaCl$$
  • $${ H }_{ 2 }S + KH$$
  • $$NaHS+HCl$$
  • $${ H }_{ 2 }{ SO }_{ 4 }+{ K }_{ 2 }S$$
Which of the following is an example of weak electrolyte?
  • $$H_3BO_3$$
  • $$H_2SO_4$$
  • $$HNO_3$$
  • $$HClO_3$$
One liter of solution contains $${ 10 }^{ -5 }$$ moles of $${ H }^{ + }$$ ions at $$ { 25 }^{ o }C$$.Percentage ionisation of water in solution is:
  • $$1.8\times { 10 }^{ -7 }\%$$
  • $$1.8\times { 10 }^{ -5 }\%$$
  • $$3.6\times { 10 }^{ -9 }\%$$
  • $$1.8\times { 10 }^{ -11 }\%$$
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 $$X{ \left( OH \right)  }_{ 3 }$$ is 100% where as second dissociation is 50% and third dissociation is negligible then the pH of $$4\times { 10 }^{ -3 }$$ $$M\quad X{ \left( OH \right)  }_{ 3 }$$ 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. $${K_a}$$ for HA is $$1.8 \times {10^{ - 6}}$$ 
  • 5.44
  • 6.44
  • 6.0
  • 4.73
 At $$25^{o}C$$, the dissociation constant for pure water is given by :-
  • $${ (55.4\times  { 10 }^{ 14 } })^{ -1 }$$
  • $$ 1 \times { 10 }^{ -14 }$$
  • $$\dfrac { 1\times  { 10 }^{ -14 } }{ 18 } $$
  • $$none\ of\ these$$
The values of dissociation constants of some acids (at $${ 25 }^{ 0 }C$$) are as follows. Indicate which is the strongest acid in water?
  • $${ 1.4\times 10 }^{ -2 }$$
  • $${ 1.6\times 10 }^{ -4 }$$
  • $${ 4.4\times 10 }^{ -10 }$$
  • $${ 4.3\times 10 }^{ -7 }$$
Ionic product of $$H_2O$$ is $$10^{-14}$$. The $$H^+$$ ion concentration in $$0.1\ M$$ $$NaOH$$ solution is:
  • $$10^{-11}\ M$$
  • $$10^{-13}\ M$$
  • $$10^{-1}\ M$$
  • $$10^{-4}\ M$$
Which among the following salts will give basic solution on hydrolysis?
  • $${NH}_{4}Cl$$
  • $$Na{NO}_{3}$$
  • $${K}_{2}{CO}_{3}$$
  • $$KCl$$
The mass of acetic acid present in 500 ml of solution in which it is 1% ionised ($$Ka$$ of $$CH_{3}COOH=1.8\times 10^{-5}$$) 
  • 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 $${ NH }_{ 3 }$$ ($${ K }_{ b }={ 1.8\times 10 }^{ -5 }$$) and 0.01M KOH?
  • $${ 1.8\times 10 }^{ -5 }$$
  • $${ 9\times 10 }^{ -6 }$$
  • $${ 3.6\times 10 }^{ -5 }$$
  • None of the above
A buffer solution can be prepared from a mixture of:
  • $${ CH }_{ 3 }COONa$$ and $$HCl$$ in 1:1 mole ratio
  • $${ CH }_{ 3 }COONa$$ and $$CH_3COOH$$ in 1:1 mole ratio
  • $${ CH }_{ 3 }COONa$$ and $$HCl$$ in 1:2 mole ratio
  • $${ NH }_{ 4 }Cl$$ and $$NaOH$$ in 1:2 mole ratio
Which of the following has maximum $$pK_a$$ :-
  • $$CH_2FCOOH$$
  • $$CH_3ClCOOH$$
  • $$CH_3COOH$$
  • $$HCOOH$$
The solubility of CaF$$_2$$ (K$$_{sp} = 5.3\times 10^{-9}$$) in $$0.1$$ M solution of NaF would be : (Assume no reaction of cation/anion) .
  • $$5.3 \times 10^{-10}$$ M
  • $$5.3 \times 10^{-8}$$ M
  • $$5.3 \times 10^{-7}$$ M
  • $$5.3 \times 10^{-11}$$ 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?
  • $$10^{-2}$$ moles/litre
  • $$10^{-1}$$ moles/litre
  • $$10^{-12}$$ moles/litre
  • $$10^{-13}$$ moles/litre
$$K_a$$ for $$HF$$ is $$3.5\times 10^{-4}$$. Calculate $$K_b$$ for the fluoride ion.
  • $$3.5\times 10^{-4}$$
  • $$1.0\times 10^{-7}$$
  • $$2.9\times 10^{-11}$$
  • $$1.0\times 10^{-14}$$
Salt which on heating produces a mixture of two gases is :
  • $$NaNO_3$$
  • $$Bi(NO_3)_3$$
  • $$Pb(NO_3)_2$$
  • $$NH_4NO_3$$
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:
  • $$0.8\times 10^{-4}$$
  • $$1.79\times 10^{-5}$$
  • $$0.182\times 10^{-4}$$
  • $$1\times 10^{-4}$$
The unit of ionic product of water $$K_w$$ are 
  • $$Mol^{-1}L^{-1}$$
  • $$Mol^{-2}L^{-2}$$
  • $$Mol^{-2}L^{-1}$$
  • $$Mol^{2}L^{-2}$$
Oxidation number of $$Cl$$ in $${ CaOCl }_{ 2 }$$ (bleaching powder) is:
  • zero, since it contains $${ Cl }_{ 2 }$$
  • $$-1$$, since it contains $${ Cl }^{ - }$$
  • $$-1$$, since it contains $${ ClO }^{ - }$$
  • $$+1$$ and $$-1$$ since it contains $${ ClO }^{ - }$$ and $${ Cl }^{ - }$$
Solution of $$ FeCl_3 $$ and $$ H_2O $$ is :
  • Basic
  • Acidic
  • Neutral
  • None of these
The number of $$H^+$$ ions in $$1\ cc$$ of a solution of $$pH = 13$$ is:
  • $$6.023 \times 10^7$$
  • $$1 \times 10^{-13}$$
  • $$6.023 \times 10^{13}$$
  • $$1 \times 10^{16}$$
The concentration of $$\left[ {{H^ + }} \right]$$ and concentration of $$\left[ {{OH^ + }} \right]$$ of a $$0.1\,M$$ aqueous solution of $$2\% $$  ionised weak acid is [ionic product of water $$ = 1 \times {10^{ - 14}}$$]
  • $$2 \times {10^{ - 3}}M$$ and $$5 \times {10^{ - 12}}M$$
  • $$1 \times {10^{ - 3}}M$$ and $$3 \times {10^{ - 11}}M$$
  • $$0.02 \times {10^{ - 3}}M$$ and $$5 \times {10^{ - 11}}M$$
  • $$3 \times {10^{ - 2}}M$$ and $$4 \times {10^{ - 13}}M$$
Dissociation constant of $$ 0.002 M $$ acotic add collection having conduct of $$ 8 \times 10^{-5} scm^{-1} $$ & $$ \mathring {A} $$ $$ 400 s cm^2 mole^{-1} $$ 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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