Objective Chemistry for Engineering and Medical Entrance Examinations

K Rama Rao

Chapter 7

Ionic Equilibrium - all with Video Answers

Educators

Chapter Questions

Problem 1

Which of the following statements is false?
(l) According to Lewis theory electrophiles are Lewis acids while nucleophiles are Lewis bases.
(2) In Friedel-Crafts reaction, the catalysts used are Lewis acids.
(3) In complex compounds, metal ions are Lewis bases while ligands are Lewis acids.
(4) Electron-deficient molecules are Lewis acids.

Hunza Gilgit

Hunza Gilgit

Numerade Educator

Problem 2

Which statement is universally correct about an acid and a base?
(1) The number of replaceable II-atoms of an acid is called its basicity.
(2) \Lambdacids burn skin.
(3) $\Lambda$ n acid must contain at least one Il atom.
(4) $\Lambda$ n acid turns red litmus to bluc.

Hunza Gilgit

Numerade Educator

Problem 3

In water the acids $\mathrm{HClO}_{4}, \mathrm{HCl}, \mathrm{H}_{2} \mathrm{SO}_{4}$ and $\mathrm{HNO}_{3}$
exhibit the same strength as they are completely ionized in water (a base). This is called .......... of the solvent water.
(1) Strength
(2) Capacity
(3) Buffer effect
(4) Lcvelling cffect

Hunza Gilgit

Numerade Educator

Problem 4

Which is not correct for Lewis acids?
(1) They contain at least one vacant orbital.
(2) They have a tendency to accept electrons.(3) The smaller ion has greater acidic strength.
(4) In case of ions, the strength of acid is inversely proportional to its charge.

Hunza Gilgit

Numerade Educator

Problem 5

\Lambdarrange $\mathrm{II}_{2} \mathrm{SO}_{4}(\mathrm{I}), \mathrm{II}_{3} \mathrm{PO}_{4}(\mathrm{II})$ and $\mathrm{IIClO}_{4}$ (III) in
decreasing order of acidic naturc.
(1) I > III > II
(2) $\mathrm{I}>\mathrm{II}>\mathrm{III}$
(3) III $>\mathrm{II}>\mathrm{I}$
(4) $\mathrm{III}>\mathrm{I}>\mathrm{II}$

Hunza Gilgit

Numerade Educator

Problem 6

The increasing order of basic strength of $\mathrm{Cl}, \mathrm{CO}_{3}^{2}$, $\mathrm{CH}_{3} \mathrm{COO}, \mathrm{OH}, \mathrm{F}$ is
(1) $\mathrm{Cl}<\mathrm{F}<\mathrm{CH}_{3} \mathrm{COO}<\mathrm{CO}_{3}^{2}<\mathrm{OH}$
(2) $\mathrm{Cl}^{-}<\mathrm{F}^{-}<\mathrm{CO}_{3}^{2-}<\mathrm{CH}_{3} \mathrm{COO}^{-}<\mathrm{OH}^{-}$
(3) $\mathrm{CHI}_{3} \mathrm{COO}<\mathrm{Cl}<\mathrm{F}<\mathrm{CO}_{3}^{2}<\mathrm{OH}$
(4) $\mathrm{F}<\mathrm{CO}_{3}^{2}<\mathrm{Cl}<\mathrm{CII}_{3} \mathrm{COO}<\mathrm{OII}$

Hunza Gilgit

Numerade Educator

Problem 7

The wrong statement among the following is
(1) Conjugate acid-base pair differs by a proton.
(2) The conjugate base of $\mathrm{H}_{3} \mathrm{BO}_{3}$ is $\mathrm{H}_{2} \mathrm{BO}_{3}$.
(3) According to Lewis, neutralization is the formation of dative bond.
(4) According to Bronsted-Lowry theory neutralization is transfer of proton.

Hunza Gilgit

Numerade Educator

Problem 8

According to Bronsted Lowry concept the correct order of strength of bases follows the order
(1) $\mathrm{CH}_{3} \mathrm{COO}^{-}>\mathrm{OH}^{-}>\mathrm{Cl}^{-}$
(2) $\mathrm{OH}^{-}>\mathrm{CH}_{3} \mathrm{COO}^{-}>\mathrm{Cl}^{-}$
(3) $\mathrm{CH}_{3} \mathrm{COO}^{-}>\mathrm{Cl}^{-}>\mathrm{OH}^{-}$
(4) $\mathrm{OH}^{-}>\mathrm{Cl}^{-}>\mathrm{CH}_{3} \mathrm{COO}^{-}$

Hunza Gilgit

Numerade Educator

Problem 9

Arrange $\mathrm{NH}_{4}^{+}, \mathrm{H}_{2} \mathrm{O}, \mathrm{H}_{3} \mathrm{O}^{+}, \mathrm{HF}$ and $\mathrm{OH}^{-}$ in increasing
order of acidic nature
(1) OII $<\mathrm{II}_{2} \mathrm{O}<\mathrm{NII}_{4}^{+}<\mathrm{IIF}<\mathrm{H}_{3} \mathrm{O}$
(2) $\mathrm{II}_{3} \mathrm{O}^{\prime}<\mathrm{HF}>\mathrm{II}_{2} \mathrm{O}>\mathrm{NH}_{4}^{\prime}>\mathrm{OII}$
(3) $\mathrm{NII}_{4}^{\prime}<\mathrm{III}<\mathrm{II}_{3} \mathrm{O}^{\prime}<\mathrm{II}_{2} \mathrm{O}<\mathrm{OII}$
(4) $\mathrm{II}_{3} \mathrm{O}^{\prime}<\mathrm{NII}_{4}^{\prime}<\mathrm{IIF}<\mathrm{OII}<\mathrm{H}_{2} \mathrm{O}$

Hunza Gilgit

Numerade Educator

Problem 10

Hydrochloric acid is a stronger acid than acetic acid because
(1) It can neutralize large quantity of alkali.
(2) It can corrode anything it comes in contact.
(3) It ionizes completely into ions in an aqueous solution.
(4) It ionizes partially into ions in aqueous solution.

Hunza Gilgit

Numerade Educator

Problem 11

\Lambdaqucous solution of acctic acid contains
(1) $\mathrm{CII}_{3} \mathrm{COOII}, \mathrm{II}^{+}$
(2) $\mathrm{CII}_{3} \mathrm{COO}^{-}, \mathrm{II}_{3} \mathrm{O}^{-}, \mathrm{CH}_{3} \mathrm{COOH}$
(3) $\mathrm{CII}_{3} \mathrm{COO}^{-}, \mathrm{II}_{3} \mathrm{O}^{-}, \mathrm{II}^{+}$
(4) $\mathrm{CII}_{3} \mathrm{COOII}, \mathrm{CII}_{3} \mathrm{COO}^{-}, \mathrm{II}^{+}$

Hunza Gilgit

Numerade Educator

Problem 12

The conjugate base of $\left|\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{3}(\mathrm{OH})_{3}\right|$ is
(1) $\left|\mathrm{A} 1\left(\mathrm{H}_{2} \mathrm{O}\right)_{3}(\mathrm{OH})_{2} \mathrm{O}\right|$
(2) $\left|\mathrm{A} 1\left(\mathrm{H}_{2} \mathrm{O}\right)_{3}(\mathrm{OH})_{2}\right|^{\prime}$(3) $\mathrm{IAl}\left(\mathrm{H}_{2} \mathrm{O}\right)_{3}(\mathrm{OH})_{3} \mid$
(4) $\left|\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}(\mathrm{OH})_{4}\right|$

Hunza Gilgit

Numerade Educator

Problem 13

Which of the following is the strongest acid?
$(1) \mathrm{ClO}_{3}(\mathrm{OH})$
(2) $\mathrm{ClO}_{2}(\mathrm{O}[\mathrm{I})$
(3) $\mathrm{SO}(\mathrm{OH})_{2}$
(4) IICOO-

Hunza Gilgit

Numerade Educator

Problem 14

$\mathrm{Mg}(\mathrm{OH}) \mathrm{Cl}$ is an example of
(1) Acid salt
(2) Basic salt
(3) Neutral salt
(4) Amphoteric salt

Hunza Gilgit

Numerade Educator

Problem 15

Which cquilibrium can be described as Lcwis acid basc reaction but not Bronsted acid basc reaction?
(1) $\mathrm{H}_{2} \mathrm{O}+\mathrm{CH}_{3} \mathrm{COOH} \rightarrow \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{CH}_{3} \mathrm{COO}^{-}$
(2) $2 \mathrm{NH}_{3}+\mathrm{H}_{2} \mathrm{SO}_{4} \rightarrow 2 \mathrm{NH}_{4}^{+}+\mathrm{SO}_{4}^{2-}$
(3) $\mathrm{CH}_{3} \mathrm{COOH}+\mathrm{NH}_{3} \rightarrow \mathrm{CH}_{3} \mathrm{COONH}_{4}$
(4) $\left[\mathrm{Cu}\left(\mathrm{II}_{2} \mathrm{O}\right)_{4}\right]^{21}+4 \mathrm{NII}_{3} \rightarrow\left[\mathrm{Cu}\left(\mathrm{NII}_{3}\right)_{4}\right]^{2}+4 \mathrm{II}_{2} \mathrm{O}$

Hunza Gilgit

Numerade Educator

Problem 16

The acidic nature of zinc oxide is shown from the formation of the salt
(1) $\mathrm{NaZnO}_{2}$
(2) $\mathrm{Na}_{2} \mathrm{ZnO}_{2}$
(3) $\mathrm{Na}_{2} \mathrm{ZnO}_{2}$
(4) $\mathrm{ZnSO}_{4}$

Hunza Gilgit

Numerade Educator

Problem 17

$\Lambda$ is a weaker acid than $\mathrm{B}$ if
(1) $\Lambda$ is more casily decomposed than $\mathrm{B}$ when heated
(2) $\Lambda$ is not corrosive
(3) $\Lambda$ is less ionized than $B$ when dissolved in a solvent
(4) $\Lambda$ is more ionized than $B$ when dissolved in a solvent

Hunza Gilgit

Numerade Educator

Problem 18

Which is correct for equilibrium? $\mathrm{CH}_{3} \mathrm{COOII}$ ? $\mathrm{HF} \rightleftharpoons \mathrm{CH}_{3} \mathrm{COOH}_{2}^{+}$ ? $\mathrm{F}^{-}$
(1) $\mathrm{F}^{-}$ is the conjugate acid $\mathrm{of} \mathrm{CII}_{3} \mathrm{COOH}$
(2) $\mathrm{F}^{-}$ is the conjugate base of IIF
(3) $\mathrm{CII}_{3}$ COOII is the conjugate acid of $\mathrm{CII}_{3} \mathrm{COOII}_{2}^{-}$
(4) $\mathrm{CII}_{3} \mathrm{COOH}_{2}{ }^{-}$ is the conjugate basc of $\mathrm{CH}_{3} \mathrm{COOII}$

Hunza Gilgit

Numerade Educator

Problem 19

The decreasing order of acidic nature of perchloric acid, sulphuric acid and sodium bisulphate is
(1) sulphuric acid $>$ sodium bisulphate $>$ perchloric acid
(2) sodium bisulphate $>$ sulphuric acid $>$ perchloric acid
(3) perchloric acid > sodium bisulphate $>$ sulphuric acid
(4) perchloric acid > sulphuric acid $>$ sodium bisulphate

Hunza Gilgit

Numerade Educator

Problem 20

In the dissociation $\mathrm{H}_{2} \mathrm{~A} \stackrel{\kappa_{1}}{\longrightarrow} \mathrm{H}^{\prime}+\mathrm{HA}$
$\mathrm{HA} \stackrel{K_{2}}{\longrightarrow} \mathrm{H}^{\prime}+\mathrm{A}^{2}$
(1) $K_{1}$ is equal to $K_{2}$
(2) $K_{1}$ is smaller than $K_{2}$
(3) $K_{1}$ is greater than $K_{2}$
(4) $K_{1}$ is negligible

Hunza Gilgit

Numerade Educator

Problem 21

The decreasing order of the strength of bases $\mathrm{OH}$, $\mathrm{NH}_{2}, \mathrm{HC} \equiv \mathrm{C}$. and $\mathrm{CH}_{3} \mathrm{CH}_{2}$
(1) $\mathrm{CH}_{3} \mathrm{CH}_{2}>\mathrm{NH}_{2}>\mathrm{HC} \equiv \mathrm{C}>\mathrm{OH}$
(2) $\mathrm{HC} \equiv \mathrm{C}>\mathrm{CH}_{3} \mathrm{CH}_{2}>\mathrm{NH}_{2}>\mathrm{OH}$
(3) $\mathrm{OH}>\mathrm{NH}_{2}>\mathrm{HC} \equiv \mathrm{C}>\mathrm{CH}_{3}-\mathrm{CH}_{2}$
(4) $\mathrm{NH}_{2}>\mathrm{HC} \equiv \mathrm{C}>\mathrm{OH}>\mathrm{CH}_{3}-\mathrm{CH}_{2}$

Hunza Gilgit

Numerade Educator

Problem 22

Which statement is correct?
(1) $\Lambda$ n acid and its conjugate basc react to form salt and water
(2) The conjugatc basc of a weak acid is a strong base
(3) The acid $\mathrm{II}_{2} \mathrm{O}$ is its own conjugate basc
(4) The conjugate base of a strong acid is a strong basc

Hunza Gilgit

Numerade Educator

Problem 23

Which statement is correct?
(1) \Lambdall Bronsted bases are also Lcwis bases
(2) \Lambdall Lewis acids are not Bronsted acids
(3) All cations are acids and all anions are bascs
(4) $\Lambda$ ll

Hunza Gilgit

Numerade Educator

Problem 24

The dissociation constant values of three acids $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ are $1.8 \times 10^{-5}, 1.5 \times 10^{-4}$ and $5.2 \times 10^{-8}$ respectively. Correct order of increasing basic character of their conjugate bases is
(1) $\mathrm{A}>\mathrm{B}>\mathrm{C}$
(2) $B>A>C$
(3) $B<A<C$
(4) $\mathrm{A}<\mathrm{B}<\mathrm{C}$

Hunza Gilgit

Numerade Educator

Problem 25

The $10^{4} \mathrm{Ka}$ values for the acids acetic, hydrofluoric, formic and nitrous are $6.7,4.5,1.8$ and $0.18$ but not in the correct order. The correct acid strengths arc
(1) $\mathrm{HF}=0.18, \mathrm{HNO}_{2}=1.8, \mathrm{HCOOH}=4.5$,
$\mathrm{CH}_{3} \mathrm{COOH}=6.7$
(2) $\mathrm{HF}=6.7, \mathrm{HNO}_{2}=4.5, \mathrm{HCOOH}=1.8, \mathrm{CH}_{3} \mathrm{COOH}$
$=0.18$
(3) $\mathrm{HF}=1.8, \mathrm{HNO}_{2}=0.18, \mathrm{HCOOH}=4.5$,
$\mathrm{CH}_{3} \mathrm{COOH}=6.7$
(4) $\mathrm{HF}=6.7, \mathrm{HNO}_{2}=0.18, \mathrm{HCOOH}=4.5$
$\mathrm{CH}_{3} \mathrm{COOH}=1.8$

Hunza Gilgit

Numerade Educator

Problem 25

The $10^{4} \mathrm{Ka}$ values for the acids acetic, hydrofluoric, formic and nitrous are $6.7,4.5,1.8$ and $0.18$ but not in the correct order. The correct acid strengths arc
(1) $\mathrm{HF}=0.18, \mathrm{HNO}_{2}=1.8, \mathrm{HCOOH}=4.5$
$\mathrm{CH}_{3} \mathrm{COOH}=6.7$
(2) $\mathrm{HF}=6.7, \mathrm{HNO}_{2}=4.5, \mathrm{HCOOH}=1.8, \mathrm{CH}_{3} \mathrm{COOH}$
$=0.18$
(3) $\mathrm{HF}=1.8, \mathrm{HNO}_{2}=0.18, \mathrm{HCOOH}=4.5$
$\mathrm{CH}_{3} \mathrm{COOH}=6.7$
(4) $\mathrm{HF}=6.7, \mathrm{HNO}_{2}=0.18, \mathrm{HCOOH}=4.5$,
$\mathrm{CH}_{3} \mathrm{COOH}=1.8$

Hunza Gilgit

Numerade Educator

Problem 26

An clement which can cxist as a positive ion in acid solution and also as ve ion in basic solution is called
(1) Amphoteric
(2) \Lambdacidic
(3) Basic
(4) Neutral

Hunza Gilgit

Numerade Educator

Problem 27

The ionization constant of a base is $\frac{1}{10} .$ The base is described as
(1) Normal base
(2) Strong basc
(3) Weak base
(4) None of these

Hunza Gilgit

Numerade Educator

Problem 28

According to Bronsted-Lowry theory, in a neutralization reaction
(1) A salt is formed
(2) Two salts are formed(3) Two conjugate acid-base pairs are formed
(4) One conjugate acid-base pair is formed

Hunza Gilgit

Numerade Educator

Problem 29

pII of water is 7 at $25^{\circ} \mathrm{C}$. If water is heated to $70^{\circ} \mathrm{C}$ the
(1) pII will decrease and solution becomes acidic
(2) pII will increasc and solution becomes basic
(3) pII will remain constant and solution is neutral
(4) pII will decrease but solution will be neutral

Hunza Gilgit

Numerade Educator

Problem 30

Which of the following statements is wrong?
(1) $\mathrm{pH}$ of rain water is $7 .$
(2) Soda water has a pH greater than 7 .
(3) lonic product of water increases with increase in temperature.
(4) The unit of ionic product of water $K_{\mathrm{w}}$ is mole $^{2}$ litre ${ }^{2}$

Hunza Gilgit

Numerade Educator

Problem 31

The OII- ion concentration of a weak base is
(1) $C K_{b}$
(2) $\sqrt{C K_{b}}$
(3) $\sqrt{\frac{K_{\mathrm{b}}}{C}}$
(4) $\sqrt{K_{b}}$

Hunza Gilgit

Numerade Educator

Problem 32

At $90^{\circ} \mathbf{C}$ pure water has $\mathrm{H}_{3} \mathrm{O}^{\prime}=10^{6}$ mol litre $^{\prime}$. The value of $K_{\mathrm{w}}$ at $90^{\circ} \mathrm{C}$ is
(1) $10^{-6}$
(2) $10^{-12}$
(3) $10^{-14}$
(4) $10^{-8}$

Hunza Gilgit

Numerade Educator

Problem 33

Pure water is kept in a vessel and it remains exposed to atmospheric $\mathrm{CO}_{2}$ which is absorbed. Then the $\mathrm{pII}$ will be
(1) greater than 7
(2) less than 7
(3) 7
(4) depends on ionic product of water

Hunza Gilgit

Numerade Educator

Problem 34

The pil of a solution is defined as
(1) Negative logarithm of its hydrogen ion concentration
(2) Negative logarithm of the reciprocal of its hydrogen ion concentration
(3) Logarithm of its hydrogen ion concentration
(4) IIydrogen ion concentration of the solution

Hunza Gilgit

Numerade Educator

Problem 35

The $\mathrm{pH}$ of solutions $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ are $9.5,2.5,3.5$ and $5.5$, respectively. The most acidic solution is
(1) $\mathrm{A}$
(2) $\mathrm{B}$
(3) $\mathrm{C}$
(4) D

Hunza Gilgit

Numerade Educator

Problem 36

Which of the following would decrease the pII of $25 \mathrm{~mL}$ of $0.01$ molar IICl?
(1) Magnesium metal
(2) Copper powder
(3) $25 \mathrm{ml}$ of $0.005$ molar $\mathrm{NaOH}$
(4) $25 \mathrm{ml}$ of $0.05 \mathrm{M} \mathrm{HCl}$

Hunza Gilgit

Numerade Educator

Problem 37

The ionic product of water changes when
(1) an acid is added to it
(2) a base is added to it
(3) whether a base or acid is added to it
(4) temperature is changed

Hunza Gilgit

Numerade Educator

Problem 38

The pII of a solution is 5 . Its hydrogen ion concentration is decreased by hundred times, the solution will then be
(1) ncutral
(2) acidic
(3) basic
(4) morc acidic

Hunza Gilgit

Numerade Educator

Problem 39

The $\mathrm{pH}$ of a solution is increased from 3 to 6 . Its $\mathrm{H}^{-}$ ion concentration will be
(1) reduced to half
(2) doubled
(3) reduced by 1000 times
(4) increased by 1000 times

Hunza Gilgit

Numerade Educator

Problem 40

The $\mathrm{pH}$ of a $0.01 \mathrm{~N}$ solution of monobasic acid is four. Then the acid involved will be
(1) weak
(2) strong
(3) strong or weak
(4) cannot be predicted

Hunza Gilgit

Numerade Educator

Problem 41

False statement among the following is
(1) $\mathrm{pII}$ of $10^{4}(\mathrm{M})$ IICl is 4
(2) $\mathrm{pH}$ of $10^{3}(\mathrm{M}) \mathrm{HCl}$ is 3
(3) pII of $10^{6}(\mathrm{M}) \mathrm{HCl}$ is 6
(4) pII of $10^{10}(\mathrm{M})$ IICl is 10

Hunza Gilgit

Numerade Educator

Problem 42

Which of the following will have nearly equal $\mathrm{H}^{-}$ concentration?
(a) $100 \mathrm{ml} 0.1 \mathrm{M}$ HCl mixed with $50 \mathrm{ml}$ water
(b) $50 \mathrm{ml} 0.1 \mathrm{M} \mathrm{II}_{2} \mathrm{SO}_{4}$ mixed with $50 \mathrm{ml}$ water
(c) $50 \mathrm{ml} 0.1 \mathrm{M} \mathrm{II}_{2} \mathrm{SO}_{4}$ mixed with $100 \mathrm{ml}$ water
(d) $50 \mathrm{ml} 0.1 \mathrm{M}$ IICl mixcd with $50 \mathrm{ml}$ watcr
(1) a, b
(2) $\mathrm{b}, \mathrm{c}$
(3) $\mathrm{a}, \mathrm{c}$
(4) $\mathrm{c}, \mathrm{d}$

Kajal Gautam

Numerade Educator

Problem 43

The ionic product of water is defined as
(1) The product of the concentration of proton and hydroxyl ion in pure water
(2) The product of the concentration of acid and hydroxyl ion in aqueous solution
(3) The ratio of the concentration of dissociated water to the undissociated water
(4) All the above

Hunza Gilgit

Numerade Educator

Problem 44

The relation for calculating pII of a weak base is
(1) $\mathrm{pH}=\mathrm{p} K_{\mathrm{w}} \quad \frac{1}{2} \mathrm{p} K_{\mathrm{b}} \mid \frac{1}{2} \log C$
(2) $\mathrm{PH}=\mathrm{p} K_{\mathrm{w}}$ ? $\frac{1}{2} \mathrm{p} K_{\mathrm{b}} \quad \frac{1}{2} \log C$

Hunza Gilgit

Numerade Educator

Problem 45

The hydrogen ion concentration in a solution of weak acid of dissociation constant $K_{a}$ and concentration $C$ is nearly equal to
(1) $\sqrt{\frac{K_{\mathrm{u}}}{C}}$
(2) $\frac{C}{K_{\mathrm{a}}}$
(3) $K_{\mathrm{a}} \cdot C$
(4) $\sqrt{K_{\mathrm{a}} \cdot \mathrm{C}}$

Hunza Gilgit

Numerade Educator

Problem 46

The extent of ionization or degrec of dissociation increases
(1) with the increase in the concentration of solute
(2) on decreasing the temperature of the solution
(3) on adding excess of water
(4) on stirring the solution

Hunza Gilgit

Numerade Educator

Problem 47

Degrec of dissociation of weak acid and weak base are the same. If $0.001 \mathrm{M}$ solution of weak acid has $\mathrm{pII}=5.0$ then the pII of $0.001 \mathrm{M}$ weak base is
(1) 9
(2) 5
(3) 10
(4) 8

Hunza Gilgit

Numerade Educator

Problem 49

The pII of $1 \%$ ionized $0.1 \mathrm{M}$ of a weak monoprotic acid is
(1) 1
(2) 2
(3) 3
(4) 11

Hunza Gilgit

Numerade Educator

Problem 50

One litre of watcr contains $10^{-7}$ moles of II $^{+}$ ions. Degrec of ionization of watcr is
(1) $1.8 \times 10^{7} \%$
(2) $1.8 \times 10^{\circ} \%$
(3) $3.6 \times 10^{7} \%$
(4) $3.6 \times 10^{9} \%$

Hunza Gilgit

Numerade Educator

Problem 51

The dissociation constants of two acids $/ / A_{1}$, and $/ I A_{2}$ are $3.6 \times 10^{-4}$ and $1.8 \times 10^{-5}$, respectively. The relative strengths of the acids will be
(1) $1: 4$
(2) $4: 1$
(3) $1: 16$
(4) $16: 1$

Hunza Gilgit

Numerade Educator

Problem 52

For an acid
$\mathrm{CH}_{3} \mathrm{COOH}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{CH}_{3} \mathrm{COO}^{-}+\mathrm{H}_{3} \mathrm{O}^{+} ; K_{1}$
and for a base $\mathrm{CH}_{3} \mathrm{COO}^{-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{CH}_{3} \mathrm{COOH}+\mathrm{OH} ; K_{2}$
Then
(1) $K_{1} \cdot K_{2}=K_{\mathrm{w}}$
(2) $\log K_{1}+\log K_{2}=\log K_{\mathrm{w}}$
(3) $\mathrm{p} K_{1}+\mathrm{p} K_{2}=\mathrm{p} K_{\mathrm{w}}$
(4) all are correct

Kajal Gautam

Numerade Educator

Problem 53

Which of the following is correct?
1) $K_{\mathrm{a}}$ (weak acid) $\times K_{\mathrm{b}}$ (conjugate weak base) $=K_{\mathrm{v}}$
2) $K_{\mathrm{a}}$ (strong acid) $\times K_{\mathrm{b}}$ (conjugate strong base) $=K_{\mathrm{w}}$
3) $K_{\mathrm{a}}$ (weak acid) $\times K_{\mathrm{b}}$ (weak base) $=K_{\mathrm{T}}$
4) $K_{\mathrm{a}}$ (weak acid) $\times K_{\mathrm{b}}$ (conjugate strong base) $=K_{\mathrm{w}}$

Hunza Gilgit

Numerade Educator

Problem 54

Consider the following reactions
(i) $\mathrm{CO}_{3}^{2-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{HCO}_{3}^{-}+\mathrm{OH}^{-}$
(ii) $\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{2} \mathrm{CO}_{3}$
(iii) $\mathrm{NH}_{3}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{NH}_{4} \mathrm{OH}$
(iv) $\mathrm{HCl}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{Cl}^{-}$
Which pair of reactions proves that water is amphoteric?
(1) $i$ and ii
(2) ii and iii
(3) iii and iv
(4) i and iii

Rashmi Gondi

Numerade Educator

Problem 55

What is correct about ionic product of an electrolyte?
(1) it is always equal to solubility product
(2) can be < or equal to $K_{\mathrm{bp}}$
(3) always $<K_{\text {wp }}$
(4) can be < or equal to or $>K_{\text {?p }}$

Hunza Gilgit

Numerade Educator

Problem 56

The pII of a solution is $5.0 .$ To this solution sufficicnt acid is added to decrease the $\mathrm{pH}$ to $2.0 .$ The increase in hydrogen ion concentration is
(1) 1000 times
(2) $5 / 2$ times
(3) 100 times
(4) 5 times

Hunza Gilgit

Numerade Educator

Problem 57

Which addition would not change the $\mathrm{pH}$ of $10 \mathrm{ml}$ of dilute hydrochloric acid?
(1) $20 \mathrm{ml}$ of the same hydrochloric acid
(2) $5 \mathrm{ml}$ of pure water
(3) $20 \mathrm{ml}$ of purc water
(4) $10 \mathrm{ml}$ of concentrated hydrochloric acid

Hunza Gilgit

Numerade Educator

Problem 58

$0.4 \mathrm{~g}$ of $\mathrm{NaOH}$ present in I-litre solution shows the $\mathrm{pH}$
(1) 12
(2) 2
(3) 6
(4) 10

Hunza Gilgit

Numerade Educator

Problem 59

The gastric juice in our stomach contains cnough hydrochloric acid to make the hydrogen ion concentration about $0.01$ mole/litre. The pII of the gastric juice is
(1) $0.01$
(2) 1
(3) 2
(4) 14

Kajal Gautam

Numerade Educator

Problem 60

$0.2$ molar solution of formic acid is $3.2 \%$ ionized. Its ionization constant is
(1) $9.6 \times 10^{3}$
(2) $2.1 \times 10^{4}$
(3) $1.25 \times 10^{6}$
(4) $4.8 \times 10^{5}$

Hunza Gilgit

Numerade Educator

Problem 61

The $\mathrm{pH}$ of the solution containing $10 \mathrm{~mL}$ of $0.1 \mathrm{~N}$ $\mathrm{NaOH}$ and $10 \mathrm{ml}$ of $0.05 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}$ would be
(1) zero
(2) 1
(3) $>7$
(4) 7

Hunza Gilgit

Numerade Educator

Problem 62

An aqueous solution contains a substance which yiclds $4 \times 10^{3}$ mol litre ${ }^{-1}$ ion $\mathrm{II}_{3} \mathrm{O}^{+}$. If $\log 2$ is $0.3010$ the pil of the solution is
(1) $1.5$
(2) $2.398$
(3) $3.0$
(4) $3.4$

Hunza Gilgit

Numerade Educator

Problem 63

The $\mathrm{pH}$ of a $1 \times 10^{8} \mathrm{M}$ aqueous solution of $\mathrm{HCl}$ is slightly less than 7 because(1) the ionization of $\mathrm{HCl}$ is incomplete
(2) the ionization of water is negligible
(3) the ionization of water at such a low concentration of $\mathrm{HCl}$ is significant
(4) the ionization of both $\mathrm{HCl}$ and water are negligible

Hunza Gilgit

Numerade Educator

Problem 64

IIClO is a weak acid. The concentration of II $^{+}$ ions in $0.1 \mathrm{M}$ solution of IIClO $\left(K_{\mathrm{a}}=5 \times 10^{-5}\right)$ will be cqual to
(1) $7.07 \times 10^{-5} \mathrm{M}$
(2) $5 \times 10^{-7} \mathrm{M}$
(3) $5 \times 10^{-4} \mathrm{M}$
(4) $7 \times 10^{-4} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 65

The $\left|\mathrm{H}_{3} \mathrm{O}^{\prime}\right|$ in the rain water of $\mathrm{pH}=4.35$ is
(1) $4.5 \times 10^{5} \mathrm{M}$
(2) $6.5 \times 10^{5} \mathrm{M}$
(3) $9.5 \times 10^{5} \mathrm{M}$
(4) $12.5 \times 10^{5} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 66

The $\mid \mathrm{OH}$ I in $100 \mathrm{~mL}$ of $0.015 \mathrm{M} \mathrm{HCl}(\mathrm{aq})$ is
(1) $5 \times 10^{-12} \mathrm{M}$
(2) $3 \times 10^{-10} \mathrm{M}$
(3) $6.7 \times 10^{-13} \mathrm{M}$
(4) $2.0 \times 10^{-9} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 67

Which solution will have pII closer to $1.0 ?$
(1) $100 \mathrm{~mL}$ of $(\mathrm{M} / 10) \mathrm{IICl}+100 \mathrm{~mL}$ of $(\mathrm{M} / 10)$
$\mathrm{NaOII}$
(2) $55 \mathrm{~mL}$ of $(\mathrm{M} / 10)$ IICl $145 \mathrm{~mL}$ of $(\mathrm{M} / 10) \mathrm{NaOII}$
(3) $10 \mathrm{~mL}$ of $(\mathrm{M} / 10)$ IICl ? $90 \mathrm{~mL}$ of $(\mathrm{M} / 10) \mathrm{NaOII}$
(4) $75 \mathrm{~mL}$ of $(\mathrm{M} / 10) \mathrm{IICl}$ ? $25 \mathrm{~mL}$ of $(\mathrm{M} / 10) \mathrm{NaOII}$

Hunza Gilgit

Numerade Educator

Problem 68

The $\mathrm{pH}$ of a solution produced when an aqueous solution of strong acid $\mathrm{pH} 5$ mixed with equal volume of an aqueous solution of strong acid of $\mathrm{pH} 3$ is
(1) $3.3$
(2) $3.5$
(3) $4.5$
(4) $4.0$

Hunza Gilgit

Numerade Educator

Problem 69

Which of the following when added to $25 \mathrm{~mL}$ of a $1.0 \mathrm{M}$ solution of sodium hydroxide would cause the largest change in $\mathrm{pH}$ ?
(1) $25 \mathrm{cc}$ of $1.0 \mathrm{M} \mathrm{HCl}$
(2) $25 \mathrm{cc}$ of $2.0 \mathrm{M} \mathrm{HCl}$
(3) $25 \mathrm{cc}$ of $0.5 \mathrm{M} \mathrm{HCl}$
(4) $25 \mathrm{cc}$ of distilled water

Hunza Gilgit

Numerade Educator

Problem 70

The pII of a soft drink is $3.82$. Its II- ion concentration will be
(1) $1.96 \times 10^{-2} \mathrm{~mol} /$ litre
(2) $1.96 \times 10^{-3}$ mol/litre
(3) $1.5 \times 10^{-4}$ mol/litre
(4) $1.96 \times 10^{-1}$ mol/litre

Hunza Gilgit

Numerade Educator

Problem 71

The phenomenon of interaction of anions and cations furnished by clectrolyte with $\mathrm{II}^{+}$ and OIT - ions of water to producc acidic nature or alkalinity is known as hydrolysis. In hydrolysis(1) The $\mathrm{pH}$ may either increase or decrease
(2) All the salts (except those made up with strong acid and base) undergo hydrolysis
(3) The variation of $\mathrm{pH}$ depends upon the nature of salt as well as on the temperature
(4) All

Hunza Gilgit

Numerade Educator

Problem 72

Thc pair of salts that does not hydrolyze
(1) $\mathrm{FcCl}_{3}, \mathrm{Sn} \mathrm{Cl}_{4}$
(2) $\mathrm{CaCl}_{2}, \mathrm{~K}_{2} \mathrm{SO}_{4}$
(3) $\mathrm{CuSO}_{4}, \Lambda 1 \mathrm{Cl}_{3}$
(4) $\mathrm{NII}_{4} \mathrm{Cl}, \mathrm{Na}_{2} \mathrm{CO}_{3}$

Hunza Gilgit

Numerade Educator

Problem 73

A salt of strong acid and a weak base is dissolved in water. Its hydrolysis in solution is
(1) not affected by heating
(2) increased by adding a strong acid
(3) suppressed by adding a strong acid
(4) suppressed by dilution

Hunza Gilgit

Numerade Educator

Problem 74

IIydrolysis constant of a salt of weak acid and weak basc is inversely proportional to
(1) Dissociation constant of weak acid
(2) Dissociation constant of weak base
(3) lonic product of water
(4) Dissociation constant of both weak acid and weak base

Hunza Gilgit

Numerade Educator

Problem 75

The aqueous solution of a salt is alkalinc. This shows that salt is made from
(1) $\Lambda$ strong acid and strong base
(2) $\Lambda$ strong acid and weak base
(3) $\Lambda$ wcak acid and weak base
(4) $\Lambda$ weak acid and strong base

Hunza Gilgit

Numerade Educator

Problem 77

Which of the following statements is falsc?
(1) Hydrolysis of the salt of strong acid and weak base is called cationic hydrolysis
(2) Hydrolysis of the salt of weak acid and strong base is known as anionic hydrolysis
(3) Aqueous solution of aluminium chloride is acidic due to hydrolysis of $\mathrm{Al}^{3}$ ion
(4) Aqueous solution of sodium carbonate is basic due to hydrolysis of $\mathrm{Na}$ ion

Hunza Gilgit

Numerade Educator

Problem 78

The pII of solutions of both ammonium acctate and sodium chloride is 7 due to
(1) IIydrolysis in both cascs
(2) The former hydrolyzes and not the latter(3) No hydrolysis in both
(4) Hydrolysis of the latter but not the former

Hunza Gilgit

Numerade Educator

Problem 79

The correct rclation for hydrolysis constant of $\mathrm{NII}_{4} \mathrm{CN}$ is
(1) $\sqrt{\frac{K_{\mathrm{w}}}{K_{u}}}$
(2) $\sqrt{\frac{K_{\mathrm{w}}}{K_{u} \times K_{\mathrm{b}}}}$
(3) $\sqrt{\frac{K_{\mathrm{h}}}{C}}$
(4) $\sqrt{\frac{K_{\mathrm{a}}}{K_{\mathrm{b}}}}$

Hunza Gilgit

Numerade Educator

Problem 80

The correct statement is
(1) $\mathrm{NII}_{4} \mathrm{Cl}$ gives an alkalinc solution in water
(2) $\mathrm{CII}_{3}$ COONa gives an acidic solution in water
(3) $\mathrm{CII}_{3} \mathrm{COOII}$ is a weak acid
(4) $\mathrm{NII}_{4} \mathrm{OII}$ is a strong base

Hunza Gilgit

Numerade Educator

Problem 81

On adding potassium cyanide to water
(1) pH will increase
(2) pH will decrease
(3) $\mathrm{pH}$ will not change
(4) electrical conductance will not change

Hunza Gilgit

Numerade Educator

Problem 82

A solution of borax has a pII of approximately
(1) $>7$
(2) $<7$
$(3)=7$
(4) betwcen 4 and 5

Hunza Gilgit

Numerade Educator

Problem 83

Which of the following statements is falsc?
(1) \Lambdaqueous solution of sodium bicarbonate is more basic than sodium carbonatc solution
(2) Solution of sodium acctate turns red litmus to blue
(3) If the dissociation constants of a weak acid and weak base constituting the salt are same its aqueous solution has a pII of 7
(4) $\Lambda$ cidic nature of copper sulphate solution is due to cationic hydrolysis

Hunza Gilgit

Numerade Educator

Problem 84

The $\mathrm{p} K_{\mathrm{s}}$ of a weak acid $\mathrm{HA}$ is greater than the $\mathrm{p} K_{\mathrm{b}}$ value of a weak base $\mathrm{BOH}$. An aqueous solution of the salt $\mathrm{AB}$ formed by the neutralization of this acid by the base will be
(1) neutral
(2) basic
(3) alkaline
(4) acidic if the solution is dilute

Hunza Gilgit

Numerade Educator

Problem 85

$K_{a}$ and $K_{b}$ values of formic acid and ammonium hydroxide are $2 \times 10^{4}$ and $1.8 \times 10^{5}$, respectively. An aqueous solution of ammonium formate is
(1) basic
(2) acidic
(3) neutral
(4) cannot be predicted

Hunza Gilgit

Numerade Educator

Problem 86

\begin{aligned}
&\text { The hydrolysis constant of a salt of weak acid }\\
&\left(K_{\mathrm{a}}=2 \times 10^{-6}\right) \text { and of a weak basc }\left(K_{\mathrm{b}}=5 \times 10^{-7}\right) \text { is }
\end{aligned}(1) 10
(2) $10^{2}$
(3) $2 \times 10^{2}$
(4) $5 \times 10^{3}$

Hunza Gilgit

Numerade Educator

Problem 87

The hydrolysis constant $K_{h}$ of a salt of sodium hydroxidc and weak acid (IIX) if the $K_{a}$ of the acid is $5 \times 10^{-6}$ is
(1) $2 \times 10^{-8}$
(2) $5 \times 10^{-6}$
(3) $2.5 \times 10^{-7}$
(4) $5 \times 10^{-9}$

Kajal Gautam

Numerade Educator

Problem 88

Which of the following statement is falsc?
(1) If $1 \mathrm{M} \mathrm{CH}_{3} \mathrm{COONa}$ is added to $1 \mathrm{M} \mathrm{CII}_{3} \mathrm{COOII}$,
pII of the solution decreases
(2) If water is added to a mixture of $\mathrm{CII}_{3} \mathrm{COOII}$ ? $\mathrm{CII}_{3}$ COONa its pII remain constant
(3) If IICl is added to acctic acid its ionization will be suppressed
(4) If a crystal of $\mathrm{NII}_{4} \mathrm{Cl}$ is added to $\mathrm{NII}_{4} \mathrm{OH}$ solution its pII increascs

Hunza Gilgit

Numerade Educator

Problem 89

The wrong statement among the following is
(1) Buffer solutions have reserve pII
(2) An acidic buffer mixturc can be prepared by mixing a solution of formic acid and sodium formate
(3) Buffer solution resist the change in pII by the addition of an acid or base
(4) addition of sodium acetate to a buffer solution of sodium acetate and acetic acid does not affect its pII

Hunza Gilgit

Numerade Educator

Problem 90

The relation for calculating $\mathrm{pH}$ of a solution containing weak acid and its salt is
(1) $\mathrm{pII}=\mathrm{p} K_{\mathrm{a}} 1 \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}$
(2) $\mathrm{pII}=\mathrm{p} K_{\mathrm{w}} \quad \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}$
(3) $\mathrm{pH}=\mathrm{p} K_{n}+\log \frac{[\Lambda \mathrm{cid}]}{[\mathrm{Salt}]}$
(4) $\widehat{\Lambda l}$

Hunza Gilgit

Numerade Educator

Problem 90

The relation for calculating $\mathrm{pH}$ of a solution containing weak acid and its salt is
(1) $\mathrm{pII}=\mathrm{p} K_{\mathrm{a}} 1 \log \frac{[\mathrm{Salt}]}{[\text { Acid }]}$
(2) $\mathrm{pH}=\mathrm{p} K_{\mathrm{n}} \quad \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}\rceil}$
(3) $\mathrm{pH}=\mathrm{p} K_{n}+\log \frac{[\Lambda \mathrm{cid}]}{[\mathrm{Salt}]}$
(4) $\mathrm{All}$

Hunza Gilgit

Numerade Educator

Problem 91

Henderson's equation used to calculate the $\mathrm{pOH}$ of a basic buffer is
(1) $\mathrm{pOH}=\mathrm{p} K_{\mathrm{b}}+\log \frac{[\text { Salt }]}{[\text { Base }]}$
(2) $\mathrm{pOH}=\mathrm{p} K_{\mathrm{b}}-\log \frac{[\mathrm{Salt}]}{[\mathrm{Basc}\rceil}$
(3) $\mathrm{pOH}=\mathrm{p} K_{\mathrm{b}}+\log \frac{[\mathrm{Base}]}{[\mathrm{Salt}]}$
(4) $\mathrm{pOH}=\mathrm{p} K_{\mathrm{b}} \quad \log \frac{[\mathrm{Basc}]}{\mid \mathrm{Salt}\rceil}$

Hunza Gilgit

Numerade Educator

Problem 92

The most important buffer in blood consists of
(1) $\mathrm{HCl}$ and $\mathrm{Cl}$
(2) $\mathrm{H}_{2} \mathrm{CO}_{3}$ and $\mathrm{HCO}_{3}$
(3) $\mathrm{H}_{2} \mathrm{CO}_{3}$ and $\mathrm{Cl}$
(4) $\mathrm{HCl}$ and $\mathrm{HCO}_{3}$

Hunza Gilgit

Numerade Educator

Problem 93

The following reactions are known to occur in the body $\mathrm{CO}_{2}$ ? $\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{II}_{2} \mathrm{CO}_{3} \rightleftharpoons \mathrm{II}^{+}$ ? $\mathrm{IICO}^{-}_{3}$
If $\mathrm{CO}_{2}$ escapes from the systcm then
(1) $\mathrm{pH}$ will decrease
(2) Hydrogen ion concentration will diminish
(3) $\mathrm{H}_{2} \mathrm{CO}_{3}$ concentration will be unaltered
(4) The forward reaction will be promoted

Hunza Gilgit

Numerade Educator

Problem 94

$A$ mixturc of a weak acid (say acctic acid) and its salts with a strong basc (say sodium acetate) acts as a buffcr solution. Which other pair has similar properties?
(1) IICl and $\mathrm{NaCl}$
(2) $\mathrm{NaOII}$ and $\mathrm{NaNO}_{3}$
(3) KOII and KCl
(4) $\mathrm{NII}_{4} \mathrm{OII}$ and $\mathrm{NII}_{4} \mathrm{Cl}$

Hunza Gilgit

Numerade Educator

Problem 95

The following equilibrium exists in an aqueous solution $\mathrm{CH}_{3} \mathrm{COOH} \rightleftharpoons \mathrm{CH}_{3} \mathrm{COO}+\mathrm{H}$
If dil. IICl is added to this solution
(1) the cquilibrium constant will increasc
(2) the cquilibrium constant will decrease
(3) II $^{+}$ ion concentration will increase
(4) acctatc ion concentration will decreasc

Hunza Gilgit

Numerade Educator

Problem 96

In a buffer solution consisting of a weak acid and its salt, the ratio of concentration of salt to acid is increased 10 fold, then the $\mathrm{pH}$ of the solution will
(1) increase by one
(2) increase by 10 fold
(3) decrease by one
(4) decrease by 10 fold

Hunza Gilgit

Numerade Educator

Problem 97

Which of the following statements is wrong?
(1) for an acid buffer solution the $\mathrm{pH}$ can be increased by inereasing the concentration of salt
(2) for a basic buffer solution the pH can increased by decreasing the concentration of base(3) buffer capacity of a buffer solution is maximum when the ratio of salt/acid or base is 1
(4) the number of moles of acid or base required by one litre of buffer solution to alter its $\mathrm{pH}$ by one unit is called buffer efficiency

Hunza Gilgit

Numerade Educator

Problem 98

Which onc of the pairs given below is best suited to prepare a buffer of $\mathrm{pH}=9 ?$
(1) $\mathrm{CII}_{3} \mathrm{COOII}$ ? $\mathrm{CII}_{3} \mathrm{COO}^{-}$
(2) $\mathrm{II}_{2} \mathrm{CO}_{3}+\mathrm{IICO}_{3}^{-}$
(3) $\mathrm{NII}_{4}^{+}$ ? $\mathrm{NII}_{4} \mathrm{OH}$
(4) $\mathrm{II}_{2} \mathrm{PO}_{4}^{-1} \mathrm{IIPO}_{4}^{2-}$

Hunza Gilgit

Numerade Educator

Problem 99

Which of the following mixture can act as a buffer solution?
(1) I litre of $0.2 \mathrm{~N} \mathrm{CH}_{3} \mathrm{COOH}+1$ litre of $0.2 \mathrm{~N} \mathrm{NaOH}$
(2) I litre of $0.1 \mathrm{~N} \mathrm{CH}_{3} \mathrm{COOH}+1$ litre of $0.2 \mathrm{~N} \mathrm{NaOH}$
(3) 1 litre of $0.2 \mathrm{~N} \mathrm{CH}_{3} \mathrm{COOH}+1$ litre of $0.1 \mathrm{~N} \mathrm{NaOH}$
(4) All the above

Hunza Gilgit

Numerade Educator

Problem 100

pII of which of the following buffer will slightly alter on addition of a strong base
(1) $\mathrm{CII}_{3} \mathrm{COOII}+\mathrm{CII}_{3} \mathrm{COONa}$
(2) $\mathrm{NII}_{4} \mathrm{OII}+\mathrm{NII}_{4} \mathrm{Cl}$
(3) Boric acid 1 Borax
(4) Nonc

Hunza Gilgit

Numerade Educator

Problem 101

When acid is added to a buffer solution composed of a weak base (B) and its salt with strong acid, then the reaction which occur to maintain the $\mathrm{pH}$ is
(1) $\mathrm{B}+\mathrm{H}_{3} \mathrm{O}^{+} \longrightarrow \mathrm{BH}^{+}+\mathrm{H}_{2} \mathrm{O}$
(2) $\mathrm{OH}^{-}+\mathrm{BH}^{+} \longrightarrow \mathrm{B}+\mathrm{H}_{2} \mathrm{O}$
(3) $\mathrm{B}+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{BH}^{-}+\mathrm{OH}^{-}$
(4) $\mathrm{BH}^{+}+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{B}+\mathrm{H}_{3} \mathrm{O}^{+}$

Hunza Gilgit

Numerade Educator

Problem 102

$10 \mathrm{~mL}$ of a solution contains $0.1 \mathrm{M} \mathrm{NII}_{4} \mathrm{Cl}$ ? $0.01 \mathrm{M}$
$\mathrm{NII}_{4} \mathrm{OII}$. Which addition would not change the pII of the solution?
(1) Adding $1 \mathrm{~mL}$ of water
(2) Adding $5 \mathrm{~mL}$ of $0.1 \mathrm{M} \mathrm{NH}_{4} \mathrm{Cl}$
(3) Adding $5 \mathrm{~mL}$ of $0.1 \mathrm{M} \mathrm{NH}_{4} \mathrm{OH}$
(4) Adding $10 \mathrm{~mL}$ of $0.1 \mathrm{M} \mathrm{NH}_{4} \mathrm{C} 1$

Hunza Gilgit

Numerade Educator

Problem 103

The $\mathrm{H}^{-}$ ion concentration of $0.001 \mathrm{M}$ acetic acid (If $K_{\mathrm{u}}=1.8 \times 10^{-5}$ ) is $1.34 \times 10^{-4} \mathrm{~g}$ ion/litre. The $\mathrm{H}^{-}$ ion
concentration if $0.164 \mathrm{~g}$ of $\mathrm{CH}_{3} \mathrm{COONa}$ is added to 1 litre of $0.001 \mathrm{M} \mathrm{CH}_{3} \mathrm{COOH}$ will be
(1) $9 \times 10^{-6}$
(2) $18 \times 10^{-6}$
(3) $4.5 \times 10^{-6}$
(4) $5 \times 10^{-6}$

Rashmi Gondi

Numerade Educator

Problem 104

$K_{a}$ for $H C N$ is $5 \times 10^{10}$ at $25^{\circ} \mathrm{C}$. For maintaining a constant $\mathrm{pH}$ of 9, the volume of $5 \mathrm{M} \mathrm{KCN}$ solution required to be added to $10 \mathrm{ml}$ of $2 \mathrm{M}$ HCN solution is
(1) $4 \mathrm{~mL}$
(2) $7.95 \mathrm{~mL}$
(3) $2 \mathrm{~mL}$
(4) $9.3 \mathrm{~mL}$

Hunza Gilgit

Numerade Educator

Problem 105

If $50 \mathrm{~mL}$ of $0.2 \mathrm{M} \mathrm{KOH}$ is added to $40 \mathrm{~mL}$ of $0.57 \mathrm{M} \mathrm{HCOOH}$, the $\mathrm{pH}$ of the resulting solution is $\left(K_{\mathrm{a}}>1.8 \times 10^{4}\right)$
(1) $3.75$
(2) $5.6$
(3) $7.5$
(4) $3.4$

Hunza Gilgit

Numerade Educator

Problem 106

A solution prepared by dissolving cqual number of moles of IIOCl $\left(K_{\mathrm{a}}=3.2 \times 10^{-8}\right)$ and $\mathrm{NaOC} .1$ is a buffer of pII
(1) 8.0
(2) $3.2$
(3) $7.5$
(4) $4.8$

Hunza Gilgit

Numerade Educator

Problem 107

A buffer solution is prepared by mixing $10 \mathrm{~mL}$ of $1 \mathrm{M}$ acetic acid and $20 \mathrm{~mL}$ of $0.5 \mathrm{M}$ sodium acetate and then diluted to $100 \mathrm{~mL}$ with distilled water of the buffer solution
(1) $3.84$
(2) $4.76$
(3) $4.34$
(4) $5.21$

Hunza Gilgit

Numerade Educator

Problem 108

The $\mathrm{pH}$ of a buffer solution prepared by mixing $20 \mathrm{~mL}$ of $0.1 \mathrm{M} \mathrm{NH}_{4} \mathrm{OH}$ and $20 \mathrm{~mL}$ of $\mathrm{IM} \mathrm{NH}_{4} \mathrm{Cl}$ is
8.2. The $\mathrm{p} \mathrm{K}_{\mathrm{b}}$ of $\mathrm{NH}_{4} \mathrm{OH}$ is
(1) $5.8$
(2) $6.8$
(3) $4.8$
(4) $9.2$

Hunza Gilgit

Numerade Educator

Problem 109

The pII of a buffer solution prepared by mixing $50 \mathrm{~mL}$ of $0.2 \mathrm{M} \mathrm{CII}_{3} \mathrm{COOII}$ and $250 \mathrm{ml}$ of $\mathrm{CII}_{3} \mathrm{COONa}$ is
4.8. What is the concentration of $\mathrm{CII}_{3} \mathrm{COONa} ? \mathrm{p} K_{\mathrm{a}}$ of $\mathrm{CH}_{3} \mathrm{COOII}$ is $4.8$.
(1) $4.0$
(2) $0.4$
(3) $2.0$
(4) $0.2$

Hunza Gilgit

Numerade Educator

Problem 110

The $\mathrm{p} K_{\mathrm{a}}$ of certain weak acid is $4.0 .$ What should be the salt to acid ratio if we have to prepare a buffer with $\mathrm{pH}=5$ using the acid and of its salts?
(1) $4: 5$
(2) $5: 4$
(3) $10: 1$
(4) $1: 10$

Hunza Gilgit

Numerade Educator

Problem 111

Addition of $0.004$ mole of an acid to a litre of a buffer decreases the $\mathrm{pH}$ of the buffer by $0.04$. Buffer capacity is
(1) $0.004$
(2) $0.04$
(3) $0.1$
(4) 1

Hunza Gilgit

Numerade Educator

Problem 112

The use of methyl orange as an indicator in the volumetric determination of the equivalent weight of a weak acid would lead to
(1) A low value for the equivalent weight
(2) A high value for the equivalent weight
(3) No error in the value
(4) Improved accuracy

Hunza Gilgit

Numerade Educator

Problem 113

Phcnolphthalcin is not a good indicator for titrating
(1) NaOH against oxalic acid
(2) Ferrous sulphate against $\mathrm{K} \mathrm{MnO}_{4}$(3) $\mathrm{NaOH}$ against $\mathrm{HCl}$
(4) $\mathrm{NaOH}$ against $\mathrm{H}_{2} \mathrm{SO}_{4}$

Hunza Gilgit

Numerade Educator

Problem 114

Which indicator works in the pH range $89.8 ?$
(1) Phenolphthalein
(2) Methyl orangc
(3) Methyl red
(4) Litmus

Hunza Gilgit

Numerade Educator

Problem 115

The best indicator for detection of end point in titration of a weak acid and strong base is
(1) Methyl orange $(3$ to 4$)$
(2) Methyl red ( 5 to 6 )
(3) Bromothymol blue $(6$ to $7.5)$
(4) Phenolphthalein $(8$ to $9.6)$

Hunza Gilgit

Numerade Educator

Problem 116

The alkali not suitable for volumctric dctermination of IICl using phenolphthalcin as an indicator
(1) $\mathrm{NaOH}$
(2) $\mathrm{Ba}(\mathrm{OH})_{2}$
(3) $\mathrm{KOH}$
(4) $\mathrm{NH}_{4} \mathrm{OH}$

Hunza Gilgit

Numerade Educator

Problem 117

\Lambdan acid base indicator has $K_{\mathrm{a}}=3 \times 10^{-5}$. The acid form of the indicator is red and the basic form is blue. The $\left[\mathrm{II}^{+}\right]$ required to change the indicator from $75 \%$ red to $75 \%$ bluc is
(1) $8 \times 10^{-5} \mathrm{M}$
(2) $9 \times 10^{-5} \mathrm{M}$
(3) $1 \times 10^{-5} \mathrm{M}$
(4) $3 \times 10^{-4} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 118

The $\mathrm{p} K_{n}$ of an indicator is 4 . Its $\mathrm{pH}$ range is
(1) 15
(2) 35
(3) 812
(4) 58

Hunza Gilgit

Numerade Educator

Problem 119

An universal indicator
(1) consists of a single indicator which changes colour at different $\mathrm{pH}$ ranges
(2) consists of a number of indicators which give different colours at different $\mathrm{pH}$ ranges
(3) is used only in the $\mathrm{pH}$ range of 0 to 7
(4) is used only in the $\mathrm{pH}$ range of 7 to 14

Hunza Gilgit

Numerade Educator

Problem 120

The colour change of an acid-base indicator is due to the formation of
(1) Benzenoid structure
(2) Quinonoid structure
(3) Ionic structure
(4) Covalent bond

Hunza Gilgit

Numerade Educator

Problem 121

Colour of the indicator is determined by the ratio
(1) $|\ln | /|\mathrm{H}|_{n} \mid$
(2) |HIn|/|ln |
(3) $|\ln | /\left|H^{\prime}\right|$
(4) $|\ln | /|\mathrm{OH}|$

Hunza Gilgit

Numerade Educator

Problem 122

End point in acid base titration is the point where
(1) the base is added to the acid
(2) the base is exactly neutralized with acid
(3) the acid is found in slight excess
(4) none

Hunza Gilgit

Numerade Educator

Problem 123

The $\mathrm{p} K_{\mathrm{a}}$ values of $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ are $1.5,4.0,5.5$
and $9.4$, respectively for a titration at the end point range if neutralization is in between $6.5$ and $10.5$. The best suitable indicator is
(1) $\mathrm{A}$
(2) $B$
(3) $\mathrm{C}$
(4) D

Hunza Gilgit

Numerade Educator

Problem 124

Which onc of the following is not a postulate of Ostwald's theory of indicators?
(1) The colour of an indicator in solution is duc to the ions furnished by it
(2) The colour of an indicator is duc to the ions furnished by acidic substancc
(3) \Lambdall indicators are weak acids or bases
(4) \Lambdacidic indicators show decp colour in acidic solutions and vice versa

Hunza Gilgit

Numerade Educator

Problem 125

Which one of the following statements is not correct according to quinonoid theory of indicators?
(1) \Lambdall indicators are organic compounds, i.c., benzenc ring derivatives
(2) One of the benzene rings in the indicator molccules exists in two forms, i.c., benzenoid form and quinonoid form
(3) One form of indicator exists in acidic medium and the other form exists in the basic medium
(4) The benzenoid form has dark colour and quinonoid a light colour

Hunza Gilgit

Numerade Educator

Problem 126

If the solubility of lithium sodium hexafluoroaluminate $\mathrm{Li}_{3} \mathrm{Na}_{3}\left(\mathrm{~A} / \mathrm{F}_{6}\right)_{2}$ is "a" mol/litre, its solubility product is equal to(1) $\mathrm{a}^{2}$
(2) $12 a^{2}$
(3) $18 a^{3}$
(4) $2916 \mathrm{a}^{8}$

Hunza Gilgit

Numerade Educator

Problem 127

The solubility of $\Lambda \mathrm{gCl}$ in water at $10^{\circ} \mathrm{C}$ is $6.2 \times$ $10^{-6} \mathrm{~mol} /$ litre. The $K_{\mathrm{p}}$ of $\Lambda \mathrm{gCl}$ is
(1) $\left[6.2 \times 10^{6}\right]^{2}$
(2) $\left[6.2 \times 10^{-6}\right]^{2}$
(3) $6.2 \times\left(10^{-6}\right)^{2}$
(4) $(6.2)^{2} \times 10^{-6}$

Hunza Gilgit

Numerade Educator

Problem 128

$K_{\mathrm{sp}}$ of $\mathrm{AgCl}$ at $18^{\circ} \mathrm{C}$ is $1.8 \times 10^{10}$. If $\mathrm{Ag}$ of solution is $4 \times 10^{3}$ mol/litre, the Cl that must exceed before $\mathrm{AgCl}$ is precipitated would be
(1) $4.5 \times 10^{-8} \mathrm{~mol} /$ litre
(2) $7.2 \times 10^{-13} \mathrm{~mol} /$ litrc
(3) $4.0 \times 10^{-3} \mathrm{~mol} /$ litre
(4) $4.5 \times 10^{-7} \mathrm{~mol} /$ itre

Hunza Gilgit

Numerade Educator

Problem 129

In which of the following solutions the solubility of AgCl will be maximum?
(1) $0.1 \mathrm{M} \mathrm{AgNO}_{3}$
(2) water
(3) $0.1 \mathrm{M} \mathrm{NaC} 1$
(4) $0.1 \mathrm{M} \mathrm{KCl}$c

Hunza Gilgit

Numerade Educator

Problem 130

The solubility of $\mathrm{PbCl}_{2}$ in water is $0.01 \mathrm{M}$ at $25^{\circ} \mathrm{C}$. Its maximum concentration in $0.1 \mathrm{M} \mathrm{NaCl}$ will $\mathrm{bc}$
(1) $2 \times 10^{-3} \mathrm{M}$
(2) $1 \times 10^{-4} \mathrm{M}$
(3) $1.6 \times 10^{-2} \mathrm{M}$
(4) $4 \times 10^{-4} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 131

A saturated solution of calcium fluoride contains $2 \times$ $10^{4}$ moles of the salt per litre of the solution. Its $K_{w}$ is
(1) $8 \times 10^{-18}$
(2) $3.2 \times 10^{-11}$
(3) $4 \times 10^{-6}$
(4) $1.43 \times 10^{-9}$

Hunza Gilgit

Numerade Educator

Problem 132

Solubility of $\mathrm{AgCl}$ at $20^{\circ} \mathrm{C}$ is $1.435 \times 10^{3} \mathrm{~g}$ per litre. The solubility product of $\mathrm{AgCl}$ is
(1) $1 \times 10^{5}$
(2) $1 \times 10^{10}$
(3) $1.435 \times 10^{5}$
(4) $108 \times 10^{3}$

Hunza Gilgit

Numerade Educator

Problem 133

The solubility product of a sparingly soluble salt $\Lambda \mathrm{B}$ at room temperature is $1.21 \times 10^{-6} .$ Its molar solubility is
(1) $1.21 \times 10^{-6}$
(2) $1.21 \times 10^{-3}$
(3) $1.1 \times 10^{-4}$
(4) $1.1 \times 10^{-3}$

Hunza Gilgit

Numerade Educator

Problem 134

When equal volumes of the following solutions are mixed, precipitation of $\mathrm{AgCl}\left(K_{\mathrm{pp}}=1.8 \times 10^{10}\right)$ will occur only with
(1) $10^{-4} \mathrm{M}\left(\mathrm{Ag}^{-}\right)$ and $10^{-4} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$
(2) $10^{-5} \mathrm{M}\left(\Lambda \mathrm{g}^{-}\right)$ and $10^{-5} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$
(3) $10^{-6} \mathrm{M}\left(\Lambda \mathrm{g}^{-}\right)$ and $10^{-6} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$
(4) $10^{-10} \mathrm{M}\left(\Lambda \mathrm{g}^{-}\right)$ and $10^{-10} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$

Hunza Gilgit

Numerade Educator

Problem 135

The precipitate of $\mathrm{CaF}_{2}\left(K_{\mathrm{cp}}=1.7 \times 10^{10}\right)$ is obtained when equal volumes of the following are mixed
(1) $10^{4} \mathrm{M} \mathrm{Ca}^{21}+10^{4} \mathrm{MF}$
(2) $10^{2} \mathrm{M} \mathrm{Ca}^{21}+10{ }^{3} \mathrm{MF}$
(3) $10^{5} \mathrm{M} \mathrm{Ca}^{21}+10^{3} \mathrm{MF}$
(4) $10^{3} \mathrm{M} \mathrm{Ca}^{21}+10{ }^{5} \mathrm{MF}$

Hunza Gilgit

Numerade Educator

Problem 136

$K_{\text {?p }}=1.2 \times 10^{-5}$ of $\mathrm{M}_{2} \mathrm{SO}_{4}\left(\mathrm{M}^{-}\right.$ is monovalent metal
ion) at $298 \mathrm{~K}$. The maximum concentration of $\mathrm{M}^{-}$ ions that could be attained in a saturated solution of this solid at $298 \mathrm{~K}$ is
(1) $3.46 \times 10^{-3} \mathrm{M}$
(2) $7.0 \times 10^{-3} \mathrm{M}$
(3) $2.88 \times 10^{-2} \mathrm{M}$
(4) $14.4 \times 10^{-3} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 137

To $100 \mathrm{~mL}$ of $0.1 \mathrm{M} \mathrm{AgNO}_{3}$ solution, solid $\mathrm{K}_{2} \mathrm{SO}_{4}$
is added. The concentration of $\mathrm{K}_{2} \mathrm{SO}_{4}$ that shows the precipitation is $\left(K_{s p}\right.$ for $\left.\mathrm{A}_{\mathrm{g}_{2}} \mathrm{SO}_{4}=6.4 \times 10^{-5} \mathrm{M}\right)$
(1) $0.1 \mathrm{M}$
(2) $6.4 \times 10^{-3} \mathrm{M}$
(3) $6.4 \times 10^{-7} \mathrm{M}$
(4) $6.4 \times 10^{-5} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 138

$K_{\mathrm{ep}}=|\mathrm{A}|^{3}|\mathrm{~B}|^{2}$ for the salt where $\mathrm{A}$ and $\mathrm{B}$ are the
cation and anion as the case may be stands true for
(1) $\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$
(2) $\mathrm{As}_{2} \mathrm{~S}_{3}$
(3) $\mathrm{Bi}_{2} \mathrm{~S}_{3}$
(4) All are correct

Hunza Gilgit

Numerade Educator

Problem 139

If the solubility product of $\Lambda g B r O_{3}$ and $\Lambda g_{2} S O_{4}$ are $5.5 \times 10^{-5}$ and $2 \times 10^{-5}$, respectively the relationship betwecn the solubilitics of thesc can be correctly represented as(1) $\mathrm{s} \mathrm{Ag} \mathrm{BrO}_{3}>\mathrm{s} \mathrm{Ag}_{2} \mathrm{SO}_{4}$
(2) $\mathrm{s} \mathrm{AgBrO}_{3}<\mathrm{s} \Lambda \mathrm{S}_{2} \mathrm{SO}_{4}$
(3) $\mathrm{s} \mathrm{AgBrO}_{3}=\mathrm{s} \mathrm{Ag}_{2} \mathrm{SO}_{4}$
(4) $\mathrm{s} \mathrm{Ag} \mathrm{BrO}_{3} \neq \mathrm{s} \mathrm{Ag}_{2} \mathrm{SO}_{4}$

Hunza Gilgit

Numerade Educator

Problem 140

The $K_{\text {sp }}$ of $\mathrm{PoCO}_{3}$ and $\mathrm{MgCO}_{3}$ are $1.5 \times 10^{-15}$ and $1 \times 10^{-15}$, respectively at $298 \mathrm{~K}$. The concentration of $\mathrm{Pb}^{2-}$ ion in a saturated solution containing $\mathrm{MgCO}_{3}$ and $\mathrm{PbCO}_{3}$ is
(1) $1.5 \times 10^{-4} \mathrm{M}$
(2) $3 \times 10^{-8} \mathrm{M}$
(3) $2 \times 10^{-8} \mathrm{M}$
(4) $2.5 \times 10^{-8} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 141

The volume of water needed to dissolve $1 \mathrm{~g}$ of $\mathrm{BaSO}_{4}$ $\left(K_{\mathrm{m}}=1.1 \times 10^{10}\right)$ at $25^{\circ} \mathrm{C}$ is
(1) 820 litres
(2) 410 litres
(3) 205 litres
(4) 1220 litres

Hunza Gilgit

Numerade Educator

Problem 142

The solubility of $\mathrm{BaSO}_{4}$ in water is $0.00233 \mathrm{~g}$ per litre at $30^{\circ} \mathrm{C}$. The solubility of $\mathrm{BaSO}_{4}$ in $0.1 \mathrm{M}\left(\mathrm{NIL}_{4}\right)_{2} \mathrm{SO}_{4}$
solution at the samc tcmperature is
(1) $10^{5}$ mol/litre
(2) $10^{6}$ mol/litre
(3) $10^{8}$ molilitre
(4) $10^{9} \mathrm{~mol} /$ litre

Hunza Gilgit

Numerade Educator

Problem 143

Let the solubilities of $\mathrm{AgCl}$ in $\mathrm{H}_{2} \mathrm{O}, 0.01 \mathrm{M} \mathrm{CaCl}_{2}$;
$0.01 \mathrm{M} \mathrm{NaCl}$ and $0.05 \mathrm{M} \mathrm{AgNO}_{3}$ be $\mathrm{S}_{1}, \mathrm{~S}_{2}, \mathrm{~S}_{3}$ and $\mathrm{S}_{4}$
respectively. What is the correct relationship between these quantities?
(1) $S_{1}>S_{2}>S_{3}>S_{4}$
(2) $S_{1}>S_{2}=S_{3}>S_{4}$
(3) $S_{1}>S_{3}>S_{2}>S_{4}$
(4) $S_{4}>S_{2}>S_{3}>S_{1}$

Hunza Gilgit

Numerade Educator

Problem 144

The solubility products of $\mathrm{MA}, \mathrm{MB}, \mathrm{MC}$ and $\mathrm{MD}$ are $1.8 \times 10^{10}, 4 \times 10^{3}, 4 \times 10^{5}$ and $6 \times 10^{5}$, respec-
tively. If a $0.01 \mathrm{M}$ solution of $\mathrm{M} \mathrm{X}$ is added dropwise to a mixture containing $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ ions then the one to be precipitated first will be
(1) $\mathrm{MA}$
(2) $\mathrm{MB}$
(3) $\mathrm{MC}$
(4) MD

Hunza Gilgit

Numerade Educator

Problem 145

$\Lambda$ saturated solution of $\mathrm{II}_{2} \mathrm{~S}$ in $0.1 \mathrm{M} \mathrm{IICl}$ at $25^{\circ} \mathrm{C}$
contains a $\mathrm{S}^{2-}$ ion concentration of $10^{-23} \mathrm{~mol} \mathrm{~L}^{-1}$. The solubility products of some sulphidcs are: $\mathrm{CuS}=10^{-44}$, $\mathrm{FeS}=10^{-14} ; \mathrm{MnS}=10^{-15}$ and $\mathrm{CdS}=10^{-25} .$ If $0.01 \mathrm{M}$
solutions of these salts in $1 \mathrm{M}$ IICl are saturated with $\mathrm{H}_{2} \mathrm{~S}$, which of these will be precipitated?
(1) All
(2) All except MnS
(3) All except MnS and FeS
(4) Only CuS

Hunza Gilgit

Numerade Educator

Problem 146

The dissociation constant of $\mathrm{II}_{2} \mathrm{~S}$ for complete dissociation is $1.1 \times 10^{-23} \mathrm{M}^{2}$. The molarity of saturated solution of a gas is $0.1 .$ The solubility product of $\mathrm{CdS}$ is $4 \times 10^{-28} \mathrm{M}^{2}$. Find the maximum concentration of cadmium that can remain in a solution of $0.1$ IICl. Which is saturated with $\mathrm{II}_{2} \mathrm{~S} ?$
(1) $0.10 \mathrm{M}$
(2) $3.63 \times 10^{-6} \mathrm{M}$
(3) $2.5 \times 10^{-5} \mathrm{M}$
(4) $4.23 \times 10^{-6} \mathrm{M}$

Hunza Gilgit

Numerade Educator

Problem 147

When $\mathrm{NaCl}$ is added to the reaction mixture of an oil and caustic soda, the soap is thrown out because
(1) $\mathrm{NaCl}$ is an ionic compound
(2) Soap is insoluble in the presence of chloride ions
(3) The solubility product of $\mathrm{NaCl}$ decreases in the presence of soap
(4) The solubility product of the soap is excceded duc to the increased concentration of $\mathrm{Na}^{-}$ ions

Hunza Gilgit

Numerade Educator

Problem 148

Sodium carbonate cannot be used in place of ammonium carbonate for the identification of the fifth group radicals. This is because the
(1) sodium ions will interfere in the detection of the fifth group radicals
(2) concentration of carbonate ions is very low
(3) sodium will react with acidic radicals
(4) magnesium will be precipitated

Hunza Gilgit

Numerade Educator

Problem 149

Why only $\Lambda \mathrm{s}^{3+}$ gets precipitated as $\Lambda \mathrm{s}_{2} \mathrm{~S}_{3}$ not $\mathrm{Zn}^{2-}$ as $\mathrm{ZnS}$ when $\mathrm{II}_{2} \mathrm{~S}$ is passed through an acidic solution containing $\Lambda s^{3-}$ and $Z n^{2-}$ ?
(1) Solubility product of $\mathrm{As}_{2} \mathrm{~S}_{3}$ is less than that of $\mathrm{ZnS}$
(2) Enough As s' are present in the acidic medium
(3) Zinc salt does not ionize in the acidic medium
(4) Solubility product changes in the presence of an acid

Hunza Gilgit

Numerade Educator

Problem 150

The addition of $\mathrm{NaCl}$ to $\mathrm{AgCl}$ decreases the solubility of $\mathrm{AgCl}$ because
(1) solubility product decreases
(2) due to the common ion effect of $\mathrm{Cl}$
(3) solubility becomes unsaturated
(4) solution becomes supersaturated

Hunza Gilgit

Numerade Educator

Problem 151

The solubility product of barium chromate is $2.4 \times$ $10^{-10}$, the maximum concentration of barium nitrate possible without precipitation in a solution of $6 \times$ $10^{-4} \mathrm{M} \mathrm{K}_{2} \mathrm{CrO}_{4}$ is
(1) $4 \times 10^{\top} \mathrm{M}$
(2) $1.2 \times 10^{10} \mathrm{M}$
(3) $6 \times 10^{4} \mathrm{M}$
(4) $3 \times 10^{4} \mathrm{M}$

Hunza Gilgit

Numerade Educator