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Advanced Problems in Physical Chemistry for Competitive Examinations

Neeraj Kumar

Chapter 7

Ionic Equilibrium - all with Video Answers

Educators

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Section 1

Exercises I

00:28

Problem 1

When rain is accompanied by a thunder storm, the collected rain water will have a $\mathrm{pH}$ value
(a) depending on the amount of dust in air.
(b) slightly lower than that of rain water without thunderstorm.
(c) slightly higher than that when the thunder storm is not there.
(d) uninfluenced by occurrence of thunderstorm.

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Raj Aggarwal
Numerade Educator
00:31

Problem 2

pH of water is $7.0$ at $25^{\circ} \mathrm{C}$. If water is heated to $70^{\circ} \mathrm{C}$, the
(a) $\mathrm{pH}$ will decrease and the sample becomes acidic.
(b) $\mathrm{pH}$ will increase but the sample will remain neutral.
(c) pH will remain constant as 7 .
(d) pH will decrease but the sample will remain neutral.

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Raj Aggarwal
Numerade Educator
00:49

Problem 3

The degree of dissociation of water at $25^{\circ} \mathrm{C}$ is $1.8 \times 10^{-7} \%$ and density is $1.0 \mathrm{~g} \mathrm{~cm}^{-3}$. The ionic constant for water is
(a) $1.0 \times 10^{-14}$
(b) $2.0 \times 10^{-16}$
(c) $1.0 \times 10^{-16}$
(d) $1.0 \times 10^{-8}$

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Raj Aggarwal
Numerade Educator
00:30

Problem 4

The degree of dissociation of pure water at $25^{\circ} \mathrm{C}$ is found to be $1.8 \times 10^{-9}$. The dissociation constant, $K_{\mathrm{d}}$ of water, at $25^{\circ} \mathrm{C}$ is
(a) $10^{-14}$
(b) $1.8 \times 10^{-16}$
(c) $5.56 \times 10^{-13}$
(d) $1.8 \times 10^{-14}$

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Raj Aggarwal
Numerade Educator
00:52

Problem 5

What is the pH of a neutral solution at $37^{\circ} \mathrm{C}$, where $K_{w}$ equals $2.5 \times 10^{-14} ?(\log 2=0.3)$
(a) $7.0$
(b) $13.6$
(c) $6.8$
(d) $6.6$

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Raj Aggarwal
Numerade Educator
01:02

Problem 6

At $40^{\circ} \mathrm{C}$, the density of heavy water is $1.02 \mathrm{~g} / \mathrm{ml}$ and its ionic product is $5.1$ $\times 10^{-15}$. Which of the following if the only incorrect information regarding heavy water at $40^{\circ} \mathrm{C}$ ?
(a) The molar concentration of heavy water is $51 \mathrm{M}$.
(b) The dissociation constant of heavy water is $10^{-16}$.
(c) Its degree of dissociation is $10^{-8}$.
(d) The molal concentration of heavy water is $50 \mathrm{~m}$.

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Raj Aggarwal
Numerade Educator
00:29

Problem 7

The ionic product of water is $1.0 \times 10^{-14}$ at $25^{\circ} \mathrm{C}$. Assuming the density of water independent from change in temperature, the ionic product of water at $50^{\circ} \mathrm{C}$ will be
(a) $2.0 \times 10^{-14}$
(b) $5.0 \times 10^{-15}$
(c) $5.9 \times 10^{-14}$
(d) $1.0 \times 10^{-14}$

ra
Raj Aggarwal
Numerade Educator
00:36

Problem 8

The hydronium ion concentration in an aqueous solution of $\mathrm{H}_{2} \mathrm{SO}_{4}$ is $2.0 \times 10^{-4} \mathrm{M}$
at $25^{\circ} \mathrm{C}$. The hydroxide ion concentration in the solution is
(a) 0
(b) $2.0 \times 10^{-4} \mathrm{M}$
(c) $5 \times 10^{3} \mathrm{M}$
(d) $5 \times 10^{-11} \mathrm{M}$

ra
Raj Aggarwal
Numerade Educator
01:09

Problem 9

The $\mathrm{pH}$ of an aqueous solution of sodium chloride at $60^{\circ} \mathrm{C}$ is
(a) $7.0$
(b) $>7.0$
(c) $<7.0$
(d) 0

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Raj Aggarwal
Numerade Educator
00:29

Problem 10

The number of hydronium ions in $1 \mathrm{ml}$ of an aqueous solution of $\mathrm{pH} 12.0$ at $25^{\circ} \mathrm{C}$ is
(a) $0.01$
(b) $10^{-12}$
(c) $6.02 \times 10^{8}$
(d) $6.02 \times 10^{11}$

ra
Raj Aggarwal
Numerade Educator
00:43

Problem 11

The $\mathrm{pH}$ of $4.0 \times 10^{-4} \mathrm{M}-\mathrm{HNO}_{3}$ solution
is $(\log 2=0.3)$
(a) $4.6$
(b) $3.4$
(c) $3.6$
(d) $4.0$

ra
Raj Aggarwal
Numerade Educator
00:58

Problem 12

The $\mathrm{pH}$ of $0.005 \mathrm{M}-\mathrm{NaOH}$ solution is $(\log 2=0.3)$
(a) $2.3$
(b) $2.7$
(c) $11.3$
(d) $11.7$

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Raj Aggarwal
Numerade Educator
01:01

Problem 13

How many grams of $\mathrm{HCl}$ should be dissolved in sufficient water to get $500 \mathrm{ml}$ of an aqueous solution of $\mathrm{pH}, 2.0$ ?
(a) $0.01$
(b) $0.005$
(c) $0.1825$
(d) $0.365$

ra
Raj Aggarwal
Numerade Educator
00:58

Problem 14

What is the $\mathrm{pH}$ of $10^{-7} \mathrm{M}-\mathrm{HCl}$ solution at $25^{\circ} \mathrm{C}$ ?
(a) $7.0$
(b) $6.70$
(c) $6.62$
(d) $6.79$

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Raj Aggarwal
Numerade Educator
01:10

Problem 15

What mass of NaOH should be dissolved in sufficient water to get $20 \mathrm{~m}^{3}$ of an aqueous solution of $\mathrm{pH}, 7.3$, at $25^{\circ} \mathrm{C}$ ?
(a) $0.16 \mathrm{~g}$
(b) $1.6 \times 10^{-4} \mathrm{~g}$
(c) $0.04 \mathrm{~g}$
(d) $0.12 \mathrm{~g}$

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Raj Aggarwal
Numerade Educator
00:29

Problem 17

Following five solutions of $\mathrm{KOH}$ were prepared as: first, $0.1$ mole in $1 \mathrm{~L} ;$ second. $0.2$ mole in $2 \mathrm{~L}$; third, $0.3$ mole in $3 \mathrm{~L}$; fourth, $0.4$ mole in $4 \mathrm{~L} ;$ fifth, $0.5$ mole in $5 \mathrm{~L}$. The $\mathrm{pH}$ of resultant solution, when all these solutions are mixed, is
(a) 2
(b) 1
(c) 13
(d) 7

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Raj Aggarwal
Numerade Educator
00:31

Problem 18

At $90^{\circ} \mathrm{C}$, the hydronium ion concentration in pure water is $10^{-6} \mathrm{M}$. If $100 \mathrm{ml}$ of $0.5 \mathrm{M}-\mathrm{NaOH}$ solution is mixed with $250 \mathrm{ml}$ of $0.2 \mathrm{M}-\mathrm{HNO}_{3}$ solution at $90^{\circ} \mathrm{C}$,
$\mathrm{pH}$ of the resulting solution will be
(a) $7.0$
(b) $6.0$
(c) $8.0$
(d) $0.85$

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Raj Aggarwal
Numerade Educator
01:05

Problem 19

Three solutions of strong electrolytes, $25 \mathrm{ml}$ of $0.1 \mathrm{M}-\mathrm{HX}, 25 \mathrm{ml}$ of $0.1 \mathrm{M}-\mathrm{H}_{2} \mathrm{Y}$
and $50 \mathrm{ml}$ of $0.1 \mathrm{~N}-\mathrm{Z}(\mathrm{OH})_{2}$ are mixed.
pOH of the resulting solution is
(a) $1.6$
(b) $7.0$
(c) $12.4$
(d) $11.6$

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Raj Aggarwal
Numerade Educator
01:05

Problem 20

When $0.05$ moles of the following acids are dissolved in $1000 \mathrm{ml}$ of $\mathrm{H}_{2} \mathrm{O}$, the $\left[\mathrm{H}^{+}\right]$ will be greatest in
(a) $\mathrm{HNO}_{2} ; \mathrm{p} K_{\mathrm{a}}=3.0$
(b) $\mathrm{HCOOH} ; \mathrm{p} K_{\mathrm{a}}=3.75$
(c) $\mathrm{HCN} ; \mathrm{p} K_{\mathrm{a}}=9.4$
(d) $\mathrm{CH}_{3} \mathrm{COOH} ; \mathrm{p} K_{\mathrm{a}}=4.75$

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Raj Aggarwal
Numerade Educator
03:12

Problem 21

When $0.05$ moles of the following acid are dissolved in $1000 \mathrm{ml}$ of $\mathrm{H}_{2} \mathrm{O}$, the $\left[\mathrm{H}^{+}\right.$ will be greatest in
(a) $\mathrm{HNO}_{2} ; \mathrm{p} K_{\mathrm{a}}=3.0$
(b) $\mathrm{HCOOH} ; \mathrm{p} K_{\mathrm{a}}=3.75$
(c) $\mathrm{HCN} ; \mathrm{p} K_{\mathrm{a}}=9.4$
(d) $\mathrm{CH}_{3} \mathrm{COOH} ; \mathrm{p} K_{\mathrm{a}}=4.75$

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Raj Aggarwal
Numerade Educator
02:56

Problem 22

The concentration of acetate ions in $1 \mathrm{M}$ acetic acid $\left(K_{\mathrm{a}}=2 \times 10^{-5}\right)$ solution containing $0.1 \mathrm{M}-\mathrm{HCl}$ is
(a) $2 \times 10^{-1} \mathrm{M}$
(b) $2 \times 10^{-3} \mathrm{M}$
(c) $2 \times 10^{-4} \mathrm{M}$
(d) $4.4 \times 10^{-3} \mathrm{M}$c

ra
Raj Aggarwal
Numerade Educator
02:55

Problem 23

The dissociation constants of formic and acetic acids are $1.77 \times 10^{-4}$ and $1.75 \times 10^{-5}$, respectively
(a) Formic acid is $3.18$ times stronger than acetic acid, at equal concentration.
(b) Acetic acid is $3.18$ times stronger than formic acid, at equal concentrations.
$\begin{array}{lllll}\text { (c) Formic acid is } 10.11 & \text { times }\end{array}$ stronger than acetic acid, at equal concentrations.
(d) Formic acid is $10.11$ times stronger than acetic acid, at different concentrations

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Raj Aggarwal
Numerade Educator
03:54

Problem 24

The dissociation constant of acetic acid is $0.000018$ and that for cyanoacetic acid is $0.0036$ at $298 \mathrm{~K}$. What would be the ratio of volumes of the two acid solutions, each containing equal moles of the acids, so that the solutions becomes isohydric?
(a) $1: 1$
(b) $1: \sqrt{200}$
(c) $1: 200$
(d) $200: 1$

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Raj Aggarwal
Numerade Educator
02:32

Problem 25

The pKa of acetylsalicylic acid (aspirin) is $3.5 .$ The $\mathrm{pH}$ of gastric juice in human stomach is about 2 to 3 and the $\mathrm{pH}$ in the small intestine is about 8 . Aspirin will be
(a) unionized in the small intestine as well as in the stomach
(b) completely ionized in the small intestine as well as in the stomach
(c) ionized in the stomach and almost unionized in the small intestine
(d) ionized in the small intestine and almost unionized in the stomach

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Raj Aggarwal
Numerade Educator
05:45

Problem 26

The active ingredient in aspirin is acetyl salicylic acid with $K_{\mathrm{a}}=4.0 \times 10^{-9} .$ The pH of the solution obtained by dissolving two aspirin tablets (containing $0.36 \mathrm{~g}$ of acetyl salicylic acid in each tablet) in $250 \mathrm{ml}$ of water is $(\log 2=0.3)$
(a) $5.1$
(b) $8.9$
(c) $10.2$
(d) $5.25$

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Raj Aggarwal
Numerade Educator
03:29

Problem 27

For weak electrolyte, $\mathrm{AB}$, the degree of ionization would be $(V=$ volume of solution having 1 mole of electrolyte and $K$ is the ionization constant of the electrolyte)
(a) $\frac{K}{V^{2}}$
(b) $K . V$
(c) $\frac{K}{V}$
(d) $\sqrt{K \cdot V}$

ra
Raj Aggarwal
Numerade Educator
01:56

Problem 28

What would be the $\mathrm{pH}$ of an ammonia solution if the $\mathrm{pH}$ of acetic acid solution of same strength is $3.2$ ? The dissociation constants of ammonia and acetic acid are
same.
(a) $3.2$
(b) $3.8$
(c) $10.2$
(d) $10.8$

ra
Raj Aggarwal
Numerade Educator
02:22

Problem 29

Isohydric solutions are the solutions having the same concentration of hydronium ion. If $0.2 \mathrm{M}-$ HA solution is isohydric with $4 \times 10^{-4} \mathrm{M}-\mathrm{HCl}$ solution, then $K_{\mathrm{b}}$ of $\mathrm{A}^{-}$ is
(a) $8 \times 10^{-7}$
(b) $1.25 \times 10^{-8}$
(c) $1.25 \times 10^{-6}$
(d) $8 \times 10^{7}$

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Raj Aggarwal
Numerade Educator
02:11

Problem 30

If $\mathrm{p} K_{\mathrm{b}}$ for fluoride ion at $25^{\circ} \mathrm{C}$ is $10.3$, the ionization constant of hydrofluoric acid in water at this temperature is $(\log 2=0.3)$
(a) $2 \times 10^{-4}$
(b) $2 \times 10^{-3}$
(c) $2 \times 10^{-5}$
(d) $5 \times 10^{-11}$

ra
Raj Aggarwal
Numerade Educator
01:49

Problem 31

$n$ -coproic acid, $\mathrm{C}_{5} \mathrm{H}_{11} \mathrm{COOH}$, found in coconut and palm oil is used in making artificial flavours, has solubility in water equal to $11.6 \mathrm{~g} / \mathrm{L}$. The saturated solution has $\mathrm{pH}=3.0$. The $K_{\mathrm{a}}$ of acid is
(a) $10^{-6}$
(b) $10^{-5}$
(c) $2 \times 10^{-5}$
(d) $2 \times 10^{-6}$

ra
Raj Aggarwal
Numerade Educator
02:10

Problem 32

The dissociation constant of formic acid is $0.00024$. The hydrogen ion concentration in $0.002 \mathrm{M}-\mathrm{HCOOH}$ solution is nearly
(a) $6.93 \times 10^{-4} \mathrm{M}$
(b) $4.8 \times 10^{-7} \mathrm{M}$
(c) $5.8 \times 10^{-4} \mathrm{M}$
(d) $1.4 \times 10^{-4} \mathrm{M}$

ra
Raj Aggarwal
Numerade Educator
03:18

Problem 33

Calculate pH of $0.02 \mathrm{M}-$ HA solution. $K_{\mathrm{a}}$ for $\mathrm{HA}=2 \times 10^{-12} .(\log 2=0.3$
$\log 3=0.48$ )
(a) $6.65$
(b) $6.70$
(c) $6.85$
(d) $6.52$

ra
Raj Aggarwal
Numerade Educator
03:18

Problem 34

How much water must added to $300 \mathrm{ml}$ of $0.2 \mathrm{M}$ solution of $\mathrm{CH}_{3} \mathrm{COOH}$ for the degree of dissociation of the acid to double? $K_{\mathrm{a}}$ for the acetic acid $=1.8 \times 10^{-5}$.
(a) $1200 \mathrm{ml}$
(b) $300 \mathrm{ml}$
(c) $600 \mathrm{ml}$
(d) $900 \mathrm{ml}$

ra
Raj Aggarwal
Numerade Educator
02:22

Problem 35

A solution has initially $0.1 \mathrm{M}-\mathrm{HCOOH}$ and $0.2 \mathrm{M}-\mathrm{HCN} . K_{\mathrm{a}}$ of $\mathrm{HCOOH}$
$=2.56 \times 10^{-4}, K_{\mathrm{a}}$ of $\mathrm{HCN}=9.6 \times 10^{-10}$
The only incorrect statement for the solution is $(\log 2=0.3)$
(a) $\left[\mathrm{H}^{+}\right]=1.6 \times 10^{-3} \mathrm{M}$
(b) $\left[\mathrm{HCOO}^{-}\right]=1.6 \times 10^{-3} \mathrm{M}$
(c) $\left[\mathrm{CN}^{-}\right]=1.2 \times 10^{-7} \mathrm{M}$
(d) $\mathrm{pOH}=2.8$

ra
Raj Aggarwal
Numerade Educator
02:51

Problem 36

What is the $\mathrm{pH}$ of $4 \times 10^{-3} \mathrm{M}-\mathrm{Y}(\mathrm{OH})_{2}$
solution assuming the first dissociation to be $100 \%$ and second dissociation to be $50 \%$, where $Y$ represents a metal cation? $(\log 2=0.3, \log 3=0.48)$
(a) $11.78$
(b) $11.22$
(c) $2.22$
(d) $2.78$

ra
Raj Aggarwal
Numerade Educator
01:42

Problem 37

The species present in solution when $\mathrm{CO}_{2}$ is dissolved in water
(a) $\mathrm{CO}_{2}, \mathrm{H}_{2} \mathrm{CO}_{3}, \mathrm{HCO}_{3}^{-}, \mathrm{CO}_{3}^{2-}$
(b) $\mathrm{H}_{2} \mathrm{CO}_{3}, \mathrm{CO}_{3}^{2-}$
(c) $\mathrm{CO}_{3}^{2-}, \mathrm{HCO}_{3}^{-}$
(d) $\mathrm{CO}_{2}, \mathrm{H}_{2} \mathrm{CO}_{3}$

ra
Raj Aggarwal
Numerade Educator
03:34

Problem 38

An aqueous solution is prepared by dissolving $0.1$ mole $\mathrm{H}_{2} \mathrm{CO}_{3}$ in sufficient water to get $100 \mathrm{ml}$ solution at $25^{\circ} \mathrm{C}$. For $\mathrm{H}_{2} \mathrm{CO}_{3}, \quad K_{\mathrm{a} 1}=4.0 \times 10^{-6}$ and
$K_{\mathrm{a} 2}=5.0 \times 10^{-11} .$ The only incorrect equilibrium concentration is
(a) $\left[\mathrm{H}^{+}\right]=6.32 \times 10^{-4} \mathrm{M}$
(b) $\left[\mathrm{HCO}_{3}\right]=2 \times 10^{-3} \mathrm{M}$
(c) $\left[\mathrm{CO}_{3}^{2-}\right]=5 \times 10^{-11} \mathrm{M}$
(d) $\left[\mathrm{OH}^{-}\right]=5 \times 10^{-12} \mathrm{M}$

ra
Raj Aggarwal
Numerade Educator
03:45

Problem 39

Ascorbic acid (vitamin $\mathrm{C}$ ) is a diprotic acid, $\mathrm{H}_{2} \mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{6}$. What is the $\mathrm{pH}$ of a
$0.10 \mathrm{M}$ solution? The acid ionization constants are $K_{\mathrm{al}}=9.0 \times 10^{-5}$ and $K_{\mathrm{a} 2}=1.6 \times 10^{-12} \cdot(\log 2=0.3, \log 3=0.48)$
(a) $3.52$
(b) $2.52$
(c) $1.52$
(d) $2.48$

ra
Raj Aggarwal
Numerade Educator
02:55

Problem 40

The $\mathrm{pH}$ of $0.1 \mathrm{M}-\mathrm{N}_{2} \mathrm{H}_{4}$ solution is (For $\mathrm{N}_{2} \mathrm{H}_{4}, K_{\mathrm{bl}}=3.6 \times 10^{-6}, K_{\mathrm{b} 2}=6.4 \times 10^{-12}$
$\log 2=0.3, \log 3=0.48)$
(a) $3.22$
(b) $2.72$
(c) $10.78$
(d) $11.22$

ra
Raj Aggarwal
Numerade Educator
00:36

Problem 41

The dissociation constant of a weak acid $\mathrm{HX}$ is, $10^{-5}$. The buffer $\mathrm{HX}+\mathrm{NaX}$ can be best used to maintain the $\mathrm{pH}$ in the range
(a) $9-11$
(b) $2-4$
(c) $11-13$
(d) $4-6$

ra
Raj Aggarwal
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00:44

Problem 42

v

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Raj Aggarwal
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00:50

Problem 43

$\mathrm{pH}$ of $0.01 \mathrm{M}-\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$ and $0.02 \mathrm{M}$
$-\mathrm{NH}_{4} \mathrm{OH}$ buffer $\left(\mathrm{p} K_{\mathrm{a}}\right.$ of $\mathrm{NH}_{4}^{+}=9.26$ ) is
(a) $9.26+\log 2$
(b) $9.26-\log 2$
(c) $4.74+\log 2$
(d) $9.26$

ra
Raj Aggarwal
Numerade Educator
00:26

Problem 44

The addition of sodium acetate to acetic acid solution will cause
(a) increase in its $\mathrm{pH}$ value
(b) decrease in its $\mathrm{pH}$ value
(c) no change in $\mathrm{pH}$ value
(d) change in $\mathrm{pH}$ which cannot be predicted

ra
Raj Aggarwal
Numerade Educator
00:52

Problem 45

A $0.1 \mathrm{M}$ acetic acid solution is titrated against $0.1 \mathrm{M}-\mathrm{NaOH}$ solution. What would be the difference in $\mathrm{pH}$ between $1 / 4$ and $3 / 4$ stages of neutralization of the acid?
(a) $2 \log (0.75)$
(b) $2 \log (0.25)$
(c) $\log 3$
(d) $2 \log 3$

ra
Raj Aggarwal
Numerade Educator
01:33

Problem 46

An amount of $0.1$ mole of $\mathrm{CH}_{3} \mathrm{NH}_{2}$ $\left(K_{\mathrm{b}}=5 \times 10^{-4}\right)$ is mixed with $0.08$ mole of $\mathrm{HCl}$ and diluted to one litre. What will be the $\mathrm{H}^{+}$ concentration in the solution?
(a) $1.25 \times 10^{-4} \mathrm{M}$
(b) $8 \times 10^{-11} \mathrm{M}$
(c) $1.6 \times 10^{-11} \mathrm{M}$
(d) $2 \times 10^{-3} \mathrm{M}$

ra
Raj Aggarwal
Numerade Educator
00:44

Problem 47

A volume of $10 \mathrm{ml}$ of a strong acid solution of $\mathrm{pH}=2.0$ are mixed with $990 \mathrm{ml}$ of a buffer solution of $\mathrm{pH}=4.0$. The $\mathrm{pH}$ of the resulting solution will be
(a) $4.2$
(b) $6.0$
(c) $4.002$
(d) $4.0$

ra
Raj Aggarwal
Numerade Educator
00:50

Problem 48

An amount of $0.15$ mole of pyridinium chloride has been added into $500 \mathrm{ml}$ of 0.2 M pyridine solution. Calculate pH and hydroxyl ion concentration in the resulting solution assuming no change in volume. $K_{\mathrm{b}}$ for pyridine $=1.5 \times 10^{-9}$. $(\log 2=0.3, \log 0.3=0.48)$
(a) $9.0$
(b) $5.0$
(c) $8.64$
(d) $5.36$

ra
Raj Aggarwal
Numerade Educator
00:31

Problem 49

A volume of $20 \mathrm{ml}$ of $0.8 \mathrm{M}-\mathrm{HCN}$ solution is mixed with $80 \mathrm{ml}$ of $0.4 \mathrm{M}$
- NaCN solution. Calculate the pH of the resulting solution. $K_{\mathrm{a}}$ of $\mathrm{HCN}=2.5 \times 10^{-10} .$ $(\log 2=0.3)$
(a) $9.9$
(b) $9.3$
(c) $4.1$
(d) $4.7$

ra
Raj Aggarwal
Numerade Educator
01:04

Problem 50

The base imidazole has a $K_{\mathrm{b}}$ of $1.0 \times 10^{-7}$ at $25^{\circ} \mathrm{C}$. In what volumes should $0.02 \mathrm{M}$ $-\mathrm{HCl}$ and $0.02 \mathrm{M}$ imidazole be mixed to make $120 \mathrm{ml}$ of a buffer at $\mathrm{pH}=7$ ?
(a) $60 \mathrm{ml}, 60 \mathrm{ml}$
(b) $40 \mathrm{ml}, 80 \mathrm{ml}$
(c) $30 \mathrm{ml}, 90 \mathrm{ml}$
(d) $20 \mathrm{ml}, 100 \mathrm{ml}$

ra
Raj Aggarwal
Numerade Educator
01:04

Problem 50

The base imidazole has a $K_{b}$ of $1.0 \times 10^{-7}$ at $25^{\circ} \mathrm{C}$. In what volumes should $0.02 \mathrm{M}$ $-\mathrm{HCl}$ and $0.02 \mathrm{M}$ imidazole be mixed to make $120 \mathrm{ml}$ of a buffer at $\mathrm{pH}=7$ ?
(a) $60 \mathrm{ml}, 60 \mathrm{ml}$
(b) $40 \mathrm{ml}, 80 \mathrm{ml}$
(c) $30 \mathrm{ml}, 90 \mathrm{ml}$
(d) $20 \mathrm{ml}, 100 \mathrm{ml}$

ra
Raj Aggarwal
Numerade Educator
00:58

Problem 51

Separate solutions of NaW, NaX, NaY and NaZ, each of concentrations $0.1 \mathrm{M}$, has $\mathrm{pH} 7.0,9.0,10.0$ and $11.0$
respectively, at $25^{\circ} \mathrm{C}$. The strongest acid among these is
(a) $\mathrm{NaW}$
(b) NaX
(c) NaY
(d) $\mathrm{NaZ}$

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Raj Aggarwal
Numerade Educator
02:29

Problem 52

If pH of $0.001 \mathrm{M}$ potassium propionate solution be $8.0$, then the dissociation constant of propionic acid will be
(a) $10^{-3}$
(b) $10^{-2}$
(c) $10^{-2.5}$
(d) $10^{-5}$

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Raj Aggarwal
Numerade Educator
01:02

Problem 53

The correct order of increasing $\left[\mathrm{OH}^{-}\right]$ in the following aqueous solution is
(a) $0.01 \mathrm{M}-\mathrm{NaHCO}_{3}<0.01 \mathrm{M}-\mathrm{NaCN}$
$<0.01 \mathrm{M}-\mathrm{KCl}$
(b) $0.01 \mathrm{M}-\mathrm{KCl}<0.01 \mathrm{M}-\mathrm{NaCN}$
$<0.01 \mathrm{M}-\mathrm{NaHCO}_{3}$
(c) $0.01 \mathrm{M}-\mathrm{KCl}<0.01 \mathrm{M}-\mathrm{NaHCO}_{3}$
$<0.01 \mathrm{M}-\mathrm{NaCN}$
(d) $0.01 \mathrm{M}-\mathrm{NaCN}<0.01 \mathrm{M}-\mathrm{KCl}$
$<0.01 \mathrm{M}-\mathrm{NaHCO}_{3}$

Narayan Hari
Narayan Hari
Numerade Educator
00:29

Problem 54

The $\mathrm{pH}$ of solutions of both ammonium acetate and sodium chloride is 7 due to
(a) hydrolysis in both case
(b) the former hydrolyses and not the latter
(c) no hydrolysis in both
(d) hydrolysis of the latter but not the former

Hunza Gilgit
Hunza Gilgit
Numerade Educator
02:29

Problem 55

For the titration of a dibasic weak acid $\mathrm{H}_{2} \mathrm{~A}\left(p^{K_{\mathrm{a}(2)}}-p^{K_{a(1)}} \geq 2\right)$ with a strong
base, $\mathrm{pH}$ versus volume of the base graph is as shown in the figure. $p^{K_{a(1)}}$ and $p^{K_{42}}$ are equal to the $\mathrm{pH}$ values corresponding to the points:.
(a) B and D, respectively
(b) A and B, respectively
(c) $\mathrm{C}$ and $\mathrm{D}$, respectively
(d) A and C, respectively

Aadit Sharma
Aadit Sharma
Numerade Educator
02:21

Problem 56

A salt of strong acid and a weak base is dissolved in water. Its hydrolysis in solution is
(a) not affected by heating
(b) increased by adding the strong acid
(c) suppressed by adding strong acid
(d) suppressed by dilution

Mariana Roldan
Mariana Roldan
Numerade Educator
03:01

Problem 57

The curve in the figure shows the variation of $\mathrm{pH}$ during the course of titration of a weak acid, HA with a strong base $(\mathrm{NaOH})$. At which point in the titration curve is the concentration of the acid equal to that of its conjugate base?
(a) Point D
(b) Point $\mathrm{E}$
(c) Point C
(d) Point $\mathrm{B}$

Anatole Borisov
Anatole Borisov
Numerade Educator
01:41

Problem 58

The pH of $0.1$ M solution of the following compounds increases in the order
(a) $\mathrm{NaCl}<\mathrm{NH}_{4} \mathrm{Cl}<\mathrm{NaCN}<\mathrm{HCl}$
(b) $\mathrm{HCl}<\mathrm{NH}_{4} \mathrm{Cl}<\mathrm{NaCl}<\mathrm{NaCN}$
(c) $\mathrm{NaCN}<\mathrm{NH}_{4} \mathrm{Cl}<\mathrm{NaCl}<\mathrm{HCl}$
(d) $\mathrm{HCl}<\mathrm{NaCl}<\mathrm{NaCN}<\mathrm{NH}_{4} \mathrm{Cl}$

Hast Aggarwal
Hast Aggarwal
Numerade Educator
01:15

Problem 59

The pH value of $0.1 \mathrm{M}$ solutions of $\begin{array}{llll}\mathrm{CH}_{3} \mathrm{COONa} & \text { (I), } & \mathrm{CH}_{3} \mathrm{COOH} & \text { (II), }\end{array}$
$\mathrm{CH}_{3} \mathrm{COONH}_{4}$ (III), $\mathrm{NaOH}$ (IV) and
$\mathrm{HCl}(\mathrm{V})$ is in the order
(a) $\mathrm{I}<\mathrm{II}<\mathrm{III}<\mathrm{IV}<\mathrm{V}$
(b) $\mathrm{V}<\mathrm{IV}<\mathrm{III}<\mathrm{II}<\mathrm{I}$
(c) $\mathrm{V}<\mathrm{II}<\mathrm{III}<\mathrm{I}<\mathrm{IV}$
(d) $\mathrm{V}<\mathrm{II}<\mathrm{I}<\mathrm{III}<\mathrm{IV}$

Akhil Choudhary
Akhil Choudhary
Numerade Educator
01:08

Problem 60

A weak acid HX has the dissociation constant $1 \times 10^{-5} \mathrm{M}$. It forms a salt $\mathrm{NaX}$ on reaction with alkali. The percentage hydrolysis of $0.1 \mathrm{M}$ solution of $\mathrm{NaX}$ is
(a) $0.0001 \%$
(b) $0.01 \%$
(c) $0.1 \%$
(d) $0.15 \%$

Narayan Hari
Narayan Hari
Numerade Educator
00:58

Problem 61

The $\mathrm{pH}$ of an aqueous solution of $1.0 \mathrm{M}$ ammonium formate assuming complete dissociation is $\left(\mathrm{p} K_{\mathrm{a}}\right.$ of formic acid $=3.8$ and $\mathrm{p} K_{\mathrm{b}}$ of ammonia $=4.8$ )
(a) $7.0$
(b) $7.5$
(c) $6.5$
(d) $4.3$

Hast Aggarwal
Hast Aggarwal
Numerade Educator
00:57

Problem 62

What is the pH of a $0.50 \mathrm{M}$ aqueous $\mathrm{NaCN}$ solution? $\mathrm{p} K_{\mathrm{b}}$ of $\mathrm{CN}^{-}$ is $4.70 .$
$(\log 2=0.3)$
(a) $3.0$
(b) $11.0$
(c) $4.7$
(d) $9.3$

Hast Aggarwal
Hast Aggarwal
Numerade Educator
01:45

Problem 63

The $\mathrm{pH}$ at the equivalence point when a solution of $0.01 \mathrm{M}-\mathrm{CH}_{3} \mathrm{COOH}$ is titrated with a solution of $0.01 \mathrm{M}-\mathrm{NaOH}$, is $\left(\mathrm{p} K_{\mathrm{a}}\right.$
of $\mathrm{CH}_{3} \mathrm{COOH}=4.7, \log 5=0.7$ )
(a) $10.5$
(b) $3.5$
(c) $10.35$
(d) $3.65$

Akhil Choudhary
Akhil Choudhary
Numerade Educator
02:47

Problem 64

The acid ionization constant of $\mathrm{Zn}^{2+}$ is $2.0 \times 10^{-10} .$ What is the $\mathrm{pH}$ of $0.001 \mathrm{M}$
solution of $\mathrm{ZnCl}_{2} ?(\log 2=0.3)$
(a) $9.7$
(b) $4.85$
(c) $6.35$
(d) $3.35$

Anand Jangid
Anand Jangid
Numerade Educator
00:26

Problem 65

The addition of ammonium chloride to acetic acid solution will cause
(a) increase in its $\mathrm{pH}$ value
(b) decrease in its $\mathrm{pH}$ value
(c) no change in $\mathrm{pH}$ value
(d) change in $\mathrm{pH}$ which cannot be predicted

ra
Raj Aggarwal
Numerade Educator
03:37

Problem 66

The indicator constant for an acidic indicator, HIn, is $5 \times 10^{-6}$ M. This indicator appears only in the colour of acidic form when $\frac{\left[\mathrm{In}^{-}\right]}{[\mathrm{HIn}]} \leq \frac{1}{20}$ and
it appears only in the colour of basic form when $\frac{[\mathrm{HIn}]}{\left[\mathrm{In}^{-}\right]} \leq 40 .$ The pH range of indicator is $(\log 2=0.3)$
(a) $4.3-6.3$
(b) $4.0-6.6$
(c) $4.0-6.9$
(d) $3.7-6.6$

VS
Vivek Singh
Numerade Educator
02:16

Problem 67

For the indicator thymol blue, the value of $\mathrm{pH}$ is $2.0 \mathrm{when}$ half of the indicator is present in the unionized form. The percentage of the indicator in the unionized form in a solution of $4.0$ $\times 10^{-3} \mathrm{M}$ hydrogen ion concentration is
(a) $40 \%$
(b) $28.6 \%$
(c) $71.4 \%$
(d) $60 \%$

Shazia Naz
Shazia Naz
Numerade Educator
03:45

Problem 68

A certain sample of rainwater gives a yellow colour with methyl red [pH range $4.2($ red $)-6.2($ yellow $)$ ]and a yellow colour with phenol red [pH range $6.4$ (yellow) $-8.0$ (red)]. What is the approximate $\mathrm{pH}$ of the water? Is the rainwater acidic, neutral, or basic?
(a) $6.3$, acidic
(b) $6.1$, acidic
(c) $6.5$, acidic
(d) $6.3$, basic

Zaida Minjares
Zaida Minjares
Numerade Educator
00:58

Problem 69

An acid type indicator, HIn differs in colour from its conjugate base $\left(\mathrm{In}^{-}\right)$. The human eye is sensitive to colour differences only when the ratio $[\operatorname{In}] /[\mathrm{HIn}]$ is greater than 10 or smaller than $0.1$. What should be the minimum change in the $\mathrm{pH}$ of the solution to observe a complete colour change $\left(K_{\mathrm{a}}=1.0 \times 10^{-5}\right)$ ?
(a) $0.0$
(b) $1.0$
(c) $2.0$
(d) $5.0$

Hast Aggarwal
Hast Aggarwal
Numerade Educator
00:47

Problem 70

The range of most suitable indicator which should be used for titration of $\mathrm{NaX}$ $(0.1 \mathrm{M}, 10 \mathrm{ml})$ with $0.1 \mathrm{M} \mathrm{HCl}$ should be
$\left(K_{\mathrm{b}}\right.$ of $\left.\mathrm{X}-=10^{-6}\right)$
(a) $2-3$
(b) $3-5$
(c) $6-8$
(d) $8-10$

Hunza Gilgit
Hunza Gilgit
Numerade Educator
01:15

Problem 71

If ionization of $\mathrm{X}_{\mathrm{a}} \mathrm{Y}_{\mathrm{b}}$ takes place then, number of $\mathrm{Y}^{\text {a }}$ ions will be equal to
(a) bla times of $\mathrm{X}^{+\mathrm{b}}$
(b) $a / b$ times of $X^{+b}$
(c) bla times of $\mathrm{X}^{a+}$
(d) equal to $\mathrm{X}^{+b}$

Mahipal Kumawat
Mahipal Kumawat
Numerade Educator
01:37

Problem 72

The solubility of sparingly soluble salt $\mathrm{A}_{3} \mathrm{~B}_{2}$ (molar mass $=$ 'M' $\mathrm{g} / \mathrm{mol}$ ) in water is 'x' g/L. The ratio of molar concentration of $\mathrm{B}^{3}$ to the solubility product of the salt is
(a) $\frac{108 x^{5}}{M^{5}}$
(b) $\frac{x^{4}}{108 M^{4}}$
(c) $\frac{x^{4}}{54 M^{4}}$
(d) $\frac{x^{3}}{27 M^{3}}$

Narayan Hari
Narayan Hari
Numerade Educator
01:24

Problem 73

The solubility product of $\mathrm{Zn}(\mathrm{OH})_{2}$ is $10^{-14}$ at $25^{\circ} \mathrm{C}$. What would be the concentration $\mathrm{Zn}^{+2}$ ion in $0.1 \mathrm{M}-\mathrm{NH}_{4} \mathrm{OH}$ solution
which is $50 \%$ ionized?
(a) $2 \times 10$
(b) $4 \times 10^{-12}$
(c) $4 \times 10^{-8}$
(d) $2 \times 10^{-11}$

Manik Pulyani
Manik Pulyani
Numerade Educator
00:21

Problem 74

In which of the following, solubility of $\mathrm{AgCl}$ will be maximum?
(a) $0.1 \mathrm{M}-\mathrm{AgNO}_{3}$
(b) Water
(c) $0.1 \mathrm{M}-\mathrm{NH}_{3}(\mathrm{aq})$
(d) $0.1 \mathrm{M}-\mathrm{NaCl}$

Hunza Gilgit
Hunza Gilgit
Numerade Educator
01:38

Problem 75

What is the equilibrium constant of the reaction: $\mathrm{Fe}(\mathrm{OH})_{3}(\mathrm{~s})+3 \mathrm{H}_{3} \mathrm{O}^{+} \rightleftharpoons \mathrm{Fe}^{3+}$
$+6 \mathrm{H}_{2} \mathrm{O} ? K_{\mathrm{sp}}$ of $\mathrm{Fe}(\mathrm{OH})_{3}=4 \times 10^{-38}$
(a) $2.5 \times 10^{-5}$
(b) $4.0 \times 10^{4}$
(c) $4.0 \times 10^{-4}$
(d) $4 \times 10^{-80}$

Anthony Han
Anthony Han
Numerade Educator
01:01

Problem 76

The solubility product of $\mathrm{AgCl}$ is $1.0 \times 10^{-10}$. The equilibrium constant of the reaction
$\mathrm{AgCl}(\mathrm{s})+\mathrm{Br}^{-} \rightleftharpoons \mathrm{AgBr}(\mathrm{s})+\mathrm{Cl}$
is 200 and that of the reaction
$2 \mathrm{AgBr}(\mathrm{s})+\mathrm{S}^{2-} \rightleftharpoons \mathrm{Ag}_{2} \mathrm{~S}(\mathrm{~s})+2 \mathrm{Br}$
is $1.6 \times 10^{24} .$ What is the $K_{\mathrm{sp}}$ of $\mathrm{Ag}_{2} \mathrm{~S}$ ?
(a) $3.2 \times 10^{16}$
(b) $1.56 \times 10^{-49}$
(c) $3.95 \times 10^{-25}$
(d) $3.13 \times 10^{-17}$

Narayan Hari
Narayan Hari
Numerade Educator
01:38

Problem 77

What is the solubility product of $\mathrm{Al}(\mathrm{OH})_{3}$ in water. Given:
$\mathrm{Al}(\mathrm{OH})_{4}^{-}(\mathrm{aq}) \rightleftharpoons \mathrm{Al}^{3+}(\mathrm{aq})+4 \mathrm{OH}^{-}(\mathrm{aq})$
$K=1.3 \times 10^{-34}$
$\mathrm{Al}(\mathrm{OH})_{3}(\mathrm{~s})+\mathrm{OH}^{-}(\mathrm{aq}) \rightleftharpoons \mathrm{Al}(\mathrm{OH})_{4}^{-}(\mathrm{aq}) ;$
$K=38.5$
(a) $3.1 \times 10^{-35}$
(b) $5 \times 10^{-33}$
(c) $6.1 \times 10^{-33}$
(d) $5 \times 10^{-34}$

Hast Aggarwal
Hast Aggarwal
Numerade Educator
02:11

Problem 78

A recent investigation of the complexation of $\mathrm{SCN}^{-}$ with $\mathrm{Fe}^{3+}$ led to values of 125 , 20 and $1.0$ for $K_{1}, K_{2}$ and $K_{3}$, respectively. What is the dissociation constant of $\mathrm{Fe}(\mathrm{SCN})_{3}$ into its simplest ions on the basis of these data?
(a) $2.5 \times 10^{3}$
(b) $4.0 \times 10^{-4}$
(c) $1.0$
(d) $8.0 \times 10^{-3}$

ra
Raj Aggarwal
Numerade Educator
01:41

Problem 79

Solubility of $\mathrm{BaF}_{2}$ in a solution of $\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}$ will be represented by the concentration term
(a) $\left[\mathrm{Ba}^{2+}\right]$
(b) $\left[\mathrm{F}^{-}\right]$
(c) $0.5[\mathrm{~F}$ ]
(d) $2\left[\mathrm{NO}_{3}^{-}\right]$

Mary Shields
Mary Shields
Numerade Educator
01:02

Problem 80

How many times solubility of $\mathrm{CaF}_{2}$ is decreased in $4 \times 10^{-3} \mathrm{M}-\mathrm{KF}(\mathrm{aq})$ solution as compared to pure water at $25^{\circ} \mathrm{C}$. Given:
$K_{\text {sp }}\left(\mathrm{CaF}_{2}\right)=3.2 \times 10^{-11}$
(a) 50
(b) 100
(c) 500
(d) 1000

Akhil Choudhary
Akhil Choudhary
Numerade Educator
04:43

Problem 81

The solubility of $\mathrm{A}_{2} \mathrm{X}_{3}$ is $y \mathrm{~mol} \mathrm{dm}^{-3}$. It solubility product is
(a) $6 y^{4}$
(b) $64 y^{4}$
(c) $36 y^{4}$
(d) $108 y^{5}$

Aswathy M
Aswathy M
Numerade Educator
01:36

Problem 82

For a sparingly soluble salt $\mathrm{A}_{\mathrm{p}} \mathrm{B}_{\mathrm{q}}$, the relationship of its solubility product $\left(L_{\mathrm{s}}\right)$ with its solubility $(S)$ is
(a) $L_{\mathrm{s}}=S^{p+q} \cdot p^{p} \cdot q^{q}$
(b) $L_{\mathrm{s}}=S^{p+q} \cdot p^{q} \cdot q^{p}$
(c) $L_{\mathrm{S}}=S^{p q} \cdot p^{p} \cdot q^{q}$
(d) $L_{\mathrm{s}}=S^{p q} \cdot(p q)^{p+q}$

Hitendra Singh
Hitendra Singh
Numerade Educator
03:45

Problem 83

$\mathrm{Ag}^{+}+\mathrm{NH}_{3} \rightleftharpoons\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)^{+}\right] ; K_{1}=1.6 \times 10^{3}$
$\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)^{+}\right]+\mathrm{NH}_{3} \rightleftharpoons\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}\right] ;$
$K_{2}=6.8 \times 10^{3} .$

The formation constant of $\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}\right]$ is
(a) $1.08 \times 10^{7}$
(b) $6.08 \times 10^{6}$
(c) $1.08 \times 10^{3}$
(d) $1.08 \times 10^{5}$

Aswathy M
Aswathy M
Numerade Educator
02:40

Problem 84

Solubility product constant $\left(K_{\mathrm{sp}}\right)$ of salts of types $\mathrm{MX}, \mathrm{MX}_{2}$ and $\mathrm{M}_{3} \mathrm{X}$ at temperature, $T$ are $4.0 \times 10^{-8}, 3.2 \times 10^{-14}$
and $2.7 \times 10^{-15}$, respectively. Solubilities (in $\mathrm{M}$ ) of the salts at temperature, $T$, are in the order
(a) $\mathrm{MX}>\mathrm{MX}_{2}>\mathrm{M}_{3} \mathrm{X}$
(b) $\mathrm{M}_{3} \mathrm{X}>\mathrm{MX}_{2}>\mathrm{MX}$
(c) $\mathrm{MX}_{2}>\mathrm{M}_{3} \mathrm{X}>\mathrm{MX}$
(d) $\mathrm{MX}>\mathrm{M}_{3} \mathrm{X}>\mathrm{MX}_{2}$

Gaurav Priyank
Gaurav Priyank
Numerade Educator
01:01

Problem 85

The solubility of $\mathrm{AgCl}$ in water is $0.001435 \mathrm{~g}$ per litre at $15^{\circ} \mathrm{C}$. The solubility product of $\mathrm{AgCl}$ is $(\mathrm{Ag}=108, \mathrm{Cl}=35.3)$
(a) $10^{-5}$
(b) $10^{-10}$
(c) $2 \times 10^{-10}$
(d) $10^{-9}$

Narayan Hari
Narayan Hari
Numerade Educator
02:50

Problem 86

The solubility of $\mathrm{Li}_{3} \mathrm{Na}_{3}\left(\mathrm{AlF}_{6}\right)_{2}$ is
$0.0744 \mathrm{~g}$ per $100 \mathrm{ml}$ at $298 \mathrm{~K}$. Calculate the solubility product of the salt. (Atomic masses: $\mathrm{Li}=7, \mathrm{Na}=23, \mathrm{Al}=27, \mathrm{~F}=19)$
(a) $2.56 \times 10^{-22}$
(b) $2 \times 10^{-3}$
(c) $7.46 \times 10^{-19}$
(d) $3.46 \times 10^{-12}$

Ly Tran
Ly Tran
Numerade Educator
01:02

Problem 87

The solubility product of $\mathrm{CaF}_{2}$ is $1.08$ $\times 10^{-10}$. What mass of $\mathrm{CaF}_{2}$ will dissolve in $500 \mathrm{ml}$ water in order to make a saturated solution? $(\mathrm{Ca}=40, \mathrm{~F}=19)$
(a) $3 \times 10^{-4} \mathrm{~g}$
(b) $1.17 \times 10^{-2} \mathrm{~g}$
(c) $1.17 \mathrm{mg}$
(d) $3 \times 10^{-3} \mathrm{~g}$

Akhil Choudhary
Akhil Choudhary
Numerade Educator
01:06

Problem 88

The solubility product of $\mathrm{Mg}(\mathrm{OH})_{2}$ is $9.0 \times 10^{-12}$. The $\mathrm{pH}$ of an aqueous saturated solution of $\mathrm{Mg}(\mathrm{OH})_{2}$ is $(\log 1.8=0.26, \log 3=0.48)$
(a) $3.58$
(b) $10.42$
(c) $3.88$
(d) $6.76$

Hunza Gilgit
Hunza Gilgit
Numerade Educator
01:24

Problem 89

The molar solubility of $\mathrm{Zn}(\mathrm{OH})_{2}$ in $1 \mathrm{M}$ ammonia solution at room temperature is $\left(K_{\mathrm{sp}}\right.$ of $\mathrm{Zn}(\mathrm{OH})_{2}=1.6 \times 10^{-17} ; K_{\text {stab }}$ of
$\left.\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}^{2+}=1.6 \times 10^{10}\right)$
(a) $4 \times 10^{-3} \mathrm{M}$
(b) $1.58 \times 10^{-6} \mathrm{M}$
(c) $4 \times 10^{-9} \mathrm{M}$
(d) $2.56 \times 10^{-7} \mathrm{M}$

Manik Pulyani
Manik Pulyani
Numerade Educator
04:18

Problem 90

Assuming no change in volume, calculate the minimum mass of $\mathrm{NaCl}$ necessary to dissolve $0.01$ mole of $\mathrm{AgCl}$ in $100 \mathrm{~L}$ solution. $K_{\mathrm{sp}}$ of $\mathrm{AgCl}=2.0 \times 10^{-10}$ and $K_{\mathrm{i}}$
of $\mathrm{AgCl}_{2}^{-}=2.5 \times 10^{5}$
(a) $117 \mathrm{~g}$
(b) $11.7 \mathrm{~kg}$
(c) $58.5 \mathrm{~kg}$
(d) $585 \mathrm{~g}$

Marissa Turner
Marissa Turner
Numerade Educator
10:40

Problem 91

The solubility product of $\mathrm{AgC}_{2} \mathrm{O}_{4}$ at $25^{\circ} \mathrm{C}$ is $2.3 \times 10^{-1 i} \mathrm{M}^{3}$. A solution of $\mathrm{K}_{2} \mathrm{C}_{2} \mathrm{O}_{4}$
containing $0.15$ moles in $500 \mathrm{ml}$ water is shaken at $25^{\circ} \mathrm{C}$ with excess of $\mathrm{Ag}_{2} \mathrm{CO}_{3}$ till the following equilibrium is reached:
$\mathrm{Ag}_{2} \mathrm{CO}_{3}+\mathrm{K}_{2} \mathrm{C}_{2} \mathrm{O}_{4} \rightleftharpoons \mathrm{Ag}_{2} \mathrm{C}_{2} \mathrm{O}_{4}+\mathrm{K}_{2} \mathrm{CO}_{3}$
At equilibrium, the solution contains $0.035$ mole of $\mathrm{K}_{2} \mathrm{CO}_{3}$. Assuming the degree of dissociation of $\mathrm{K}_{2} \mathrm{C}_{2} \mathrm{O}_{4}$ and $\mathrm{K}_{2} \mathrm{CO}_{3}$ to be equal, calculate the solubility product of $\mathrm{Ag}_{2} \mathrm{CO}_{3}$
(a) $2.3 \times 10^{-11} \mathrm{M}^{3}$
(b) $7.0 \times 10^{-10} \mathrm{M}^{3}$
(c) $3.0 \times 10^{-13} \mathrm{M}^{3}$
(d) $7.0 \times 10^{-12} \mathrm{M}^{3}$

Samantha Grieco
Samantha Grieco
Numerade Educator
01:13

Problem 92

For the reaction $\left[\mathrm{Ag}(\mathrm{CN})_{2}\right] \rightleftharpoons \mathrm{Ag}^{+}$
$+2 \mathrm{CN}^{-}$, the equilibrium constant, at $25^{\circ} \mathrm{C}$, is $4.0 \times 10^{-19}$. Calculate the silver ion concentration in a solution which was originally $0.10$ molar in $\mathrm{KCN}$ and $0.03$ molar in $\mathrm{AgNO}_{3}$.
(a) 0
(b) $0.03 \mathrm{M}$
(c) $3 \times 10^{-19} \mathrm{M}$
(d) $1.71 \times 10^{-19} \mathrm{M}$

Akhil Choudhary
Akhil Choudhary
Numerade Educator
00:39

Problem 93

A sample of $\mathrm{AgCl}$ was treated with $5.00 \mathrm{ml}$ of $2.0 \mathrm{M} \mathrm{Na}_{2} \mathrm{CO}_{3}$ solution to
give $\mathrm{Ag}_{2} \mathrm{CO}_{3}$. The remaining solution contained $0.00355 \mathrm{~g}$ of $\mathrm{Cl}^{-}$ ions per litre. The solubility product of $\mathrm{AgCl}$ is $\left(K_{\mathrm{sp}}\right.$ of $\mathrm{Ag}_{2} \mathrm{CO}_{3}$ is $\left.8.0 \times 10^{-12}\right)$
(a) $2 \times 10^{-10}$
(b) $1 \times 10^{-10}$
(c) $4 \times 10^{-10}$
(d) $8 \times 10^{-10}$

Hunza Gilgit
Hunza Gilgit
Numerade Educator
02:35

Problem 94

Given: $\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+} \rightleftharpoons \mathrm{Ag}^{+}+2 \mathrm{NH}_{3}$
$K_{\mathrm{c}}=7.2 \times 10^{-8}$ and $K_{\mathrm{sp}}$ of $\mathrm{AgCl}=1.8 \times 10$
at $298 \mathrm{~K}$. If ammonia is added to a water solution containing excess of $\mathrm{AgCl}(\mathrm{s})$ only, calculate the concentration of the complex in $1.0 \mathrm{M}$ aqueous ammonia.
(a) $1.0 \mathrm{M}$
(b) $0.091 \mathrm{M}$
(c) $0.0455 \mathrm{M}$
(d) $0.023 \mathrm{M}$

Anthony Han
Anthony Han
Numerade Educator
01:35

Problem 95

The solubility of $\mathrm{Pb}(\mathrm{OH})_{2}$ in water is $6.0 \times 10^{-6} \mathrm{M}$. The solubility of $\mathrm{Pb}(\mathrm{OH})_{2}$
in a buffer solution of $\mathrm{pH}=8$ is
(a) $8.64 \mathrm{M}$
(b) $2.16 \times 10^{-16} \mathrm{M}$
(c) $8.64 \times 10^{-16} \mathrm{M}$
(d) $8.64 \times 10^{-4} \mathrm{M}$

Hast Aggarwal
Hast Aggarwal
Numerade Educator
01:13

Problem 96

The silver ion concentration in a $0.2 \mathrm{M}$ solution of $\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{NO}_{3}$ is $\left(K_{\mathrm{diss}}=6.8\right.$
$\left.\times 10^{-8}, 1.5^{3}=3.4\right)$
(a) $0.2 \mathrm{M}$
(b) $1.5 \times 10^{-3} \mathrm{M}$
(c) $1.16 \times 10^{-4} \mathrm{M}$
(d) $6.8 \times 10^{-8} \mathrm{M}$

Akhil Choudhary
Akhil Choudhary
Numerade Educator
03:06

Problem 97

The formation constant of $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}^{2+}$ is $1.25 \times 10^{12}$. What will be the equilibrium concentration of $\mathrm{Cu}^{2+}$ if $0.0125 \mathrm{moles}$ of $\mathrm{Cu}$ is oxidized and put into $1.0 \mathrm{~L}$ of $0.25 \mathrm{M}-\mathrm{NH}_{3}$ solution?
(a) $2.5 \times 10^{-11} \mathrm{M}$
(b) $2.5 \times 10^{-13} \mathrm{M}$
(c) $4 \times 10^{-12} \mathrm{M}$
(d) 0

Aadit Sharma
Aadit Sharma
Numerade Educator
02:55

Problem 98

The simultaneous solubilities of $\mathrm{AgSCN}$ and $\mathrm{AgBr}$ are, respectively $\left(K_{\mathrm{sp}}\right.$ of $\mathrm{AgSCN}$ $=1 \times 10^{-12}, K_{\mathrm{sp}}$ of $\left.\mathrm{AgBr}=2.1 \times 10^{-13}\right)$
(a) $9.09 \times 10^{-7} \mathrm{M}, 1.909 \times 10^{-7} \mathrm{M}$
(b) $1.909 \times 10^{-7} \mathrm{M}, 9.09 \times 10^{-7} \mathrm{M}$
(c) $9.09 \times 10^{-6} \mathrm{M}, 1.909 \times 10^{-7} \mathrm{M}$
(d) $1.1 \times 10^{-6} \mathrm{M}, 2.1 \times 10^{-7} \mathrm{M}$

Supratim Pal
Supratim Pal
Numerade Educator
03:27

Problem 99

The solubility of $\mathrm{AgCN}$ in a buffer solution of $\mathrm{pH}=3.0$ is $\left(K_{\mathrm{sp}}\right.$ of $\mathrm{AgCN}$ $=1.2 \times 10^{-16} ; K_{\mathrm{a}}$ of $\left.\mathrm{HCN}=4.8 \times 10^{-10}\right)$
(a) $1.58 \times 10^{-5} \mathrm{M}$
(b) $2.0 \times 10^{-5} \mathrm{M}$
(c) $1.58 \times 10^{-4} \mathrm{M}$
(d) $2.5 \times 10^{-9} \mathrm{M}$

Aadit Sharma
Aadit Sharma
Numerade Educator
01:39

Problem 100

The solubility of $\mathrm{PbCl}_{2}$ when it is $80 \%$ ionized is
(a) $25 \%$ less than the solubility of $\mathrm{PbCl}_{2}$ when it is $100 \%$ ionized.
(b) $50 \%$ less than the solubility of $\mathrm{PbCl}_{2}$ when it is $100 \%$ ionized.
(c) More than the solubility of $\mathrm{PbCl}_{2}$ when it is $100 \%$ ionized.
(d) is equal to the solubility of $\mathrm{PbCl}_{2}$ when it is $100 \%$ ionized.

David Collins
David Collins
Numerade Educator
01:17

Problem 101

$\begin{array}{llll}\text { Solubility } & \text { products of } & \mathrm{Mg}(\mathrm{OH})_{2} \text { , }\end{array}$
$\mathrm{Cd}(\mathrm{OH})_{2}, \mathrm{Al}(\mathrm{OH})_{3}$ and $\mathrm{Zn}(\mathrm{OH})_{2}$ are
$4 \times 10^{-11}, 8 \times 10^{-6}, 8.5 \times 10^{-23}$ and
$1.8 \times 10^{-14}$, respectively. The cation that will precipitate first as hydroxide, on adding limited quantity of $\mathrm{NH}_{4} \mathrm{OH}$ in a solution containing equimolar amount of metal cations, is
(a) $\mathrm{Al}^{3+}$
(b) $\mathrm{Zn}^{2+}$
(c) $\mathrm{Mg}^{2+}$
(d) $\mathrm{Cd}^{2+}$

Hunza Gilgit
Hunza Gilgit
Numerade Educator
03:30

Problem 102

Silver ions are slowly added in a solution with $\left[\mathrm{Br}^{-}\right]=\left[\mathrm{Cl}^{-}\right]=\left[\mathrm{CO}_{3}^{2-}\right]=\left[\mathrm{AsO}_{4}^{3-}\right]$
$=0.1 \mathrm{M}$. Which compound will precipitate first?
(a) $\operatorname{AgBr}\left(K_{\mathrm{sp}}=5 \times 10^{-13}\right)$
(b) $\mathrm{AgCl}\left(K_{\mathrm{sp}}=1.8 \times 10^{-10}\right)$
(c) $\mathrm{Ag}_{2} \mathrm{CO}_{3}\left(K_{\mathrm{sp}}=8.1 \times 10^{-12}\right)$
(d) $\mathrm{Ag}_{3} \mathrm{PO}_{4}\left(K_{\mathrm{sp}}=1 \times 10^{-22}\right)$

Lottie Adams
Lottie Adams
Numerade Educator
01:03

Problem 103

The $K_{\mathrm{sp}}$ of $\mathrm{Ag}_{2} \mathrm{CrO}_{4}=1.2 \times 10^{-11} .$ What
concentration Ag $^{+}$ ion in aqueous solution will just fail to give a precipitate of $\mathrm{Ag}_{2} \mathrm{CrO}_{4}$ with a solution in which $\left[\mathrm{CrO}_{4}^{-2}\right]=3 \times 10^{-4} \mathrm{M} ?$
(a) $10^{-3} \mathrm{M}$
(b) $10^{-1} \mathrm{M}$
(c) $10^{-4} \mathrm{M}$
(d) $2 \times 10^{-4} \mathrm{M}$

Narayan Hari
Narayan Hari
Numerade Educator
01:02

Problem 104

A $0.1$ mole of $\mathrm{AgNO}_{3}$ is dissolved in $1 \mathrm{~L}$ of $1 \mathrm{M}-\mathrm{NH}_{3} .$ If $0.01$ mole of $\mathrm{NaCl}$ is added to this solution, will $\mathrm{AgCl}(\mathrm{s})$ precipitate? $K_{\mathrm{sp}}$ for $\mathrm{AgCl}=1.8 \times 10^{-10}$ and $K_{\text {stab }}$ for $\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}=1.6 \times 10^{7} .$
(a) Yes
(b) No
(c) Addition of $\mathrm{NaCl}$ in any amount can never result precipitation.
(d) Addition of even smaller amount of $\mathrm{NaCl}$ may result precipitation.

Narayan Hari
Narayan Hari
Numerade Educator
04:52

Problem 105

In $500 \mathrm{ml}$ of $2.5 \times 10^{-5} \mathrm{M}-\mathrm{AgNO}_{3}$
solution, $2000 \mathrm{ml}$ of $5.0 \times 10^{-2} \mathrm{M}-\mathrm{NaCl}$
solution is added. The mass of precipitate of $\mathrm{AgCl}$ formed is $\left(K_{\mathrm{sp}}\right.$ of $\mathrm{AgCl}=2$ $\left.\times 10^{-10}, \mathrm{Ag}=108\right)$
(a) $1.794 \mathrm{~g}$
(b) $1.794 \mathrm{mg}$
(c) $5 \times 10^{-6} \mathrm{~g}$
(d) $1.25 \times 10^{-2} \mathrm{~g}$

Adriano Chikande
Adriano Chikande
Numerade Educator
01:05

Problem 106

The solubility product of $\mathrm{PbI}_{2}$ is $7.2 \times 10^{-9}$. The maximum mass of NaI which may be added in $500 \mathrm{ml}$ of $0.005 \mathrm{M}-\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}$
solution without any precipitation of $\mathrm{PbI}_{2}$ is $(\mathrm{I}=127)$
(a) $0.09 \mathrm{~g}$
(b) $1.2 \times 10^{-3} \mathrm{~g}$
(c) $6 \times 10^{-4} \mathrm{~g}$
(d) $1.08 \times 10^{-5} \mathrm{~g}$

Narayan Hari
Narayan Hari
Numerade Educator
03:53

Problem 107

The minimum mass of NaBr which should be added in $200 \mathrm{ml}$ of $0.0004 \mathrm{M}-\mathrm{AgNO}_{3}$
solution just to start the precipitation of AgBr. $K_{\mathrm{sp}}$ of $\mathrm{AgBr}=4 \times 10^{-13} \cdot(\mathrm{Br}=80)$
(a) $1.0 \times 10^{-9} \mathrm{~g}$
(b) $2 \times 10^{-10} \mathrm{~g}$
(c) $2.06 \times 10^{-8} \mathrm{~g}$
(d) $1.03 \times 10^{-7} \mathrm{~g}$

Natalie Almond
Natalie Almond
Numerade Educator
06:22

Problem 108

A sample of hard water contains $0.005$ mole of $\mathrm{CaCl}_{2}$ per litre. What is the minimum concentration of $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$ which must be exceeded for removing $\mathrm{Ca}^{2+}$ ions from this water sample? The solubility product of $\mathrm{CaSO}_{4}$ is $2.4 \times 10^{-5}$.
(a) $4.8 \times 10^{-3} \mathrm{M}$
(b) $1.2 \times 10^{-3} \mathrm{M}$
(c) $0.0144 \mathrm{M}$
(d) $2.4 \times 10^{-3} \mathrm{M}$

Aswathy M
Aswathy M
Numerade Educator
01:05

Problem 109

To $100 \mathrm{ml}$ of a solution, which contains $8.32 \times 10^{-3} \mathrm{~g}$ lead ions, $10^{-4}$ moles of $\mathrm{H}_{2} \mathrm{SO}_{4}$ is added. How much lead remains in the solution unprecipitated? $K_{\text {sp }}$ of $\mathrm{PbSO}_{4}=1.6 \times 10^{-7} \cdot(\mathrm{Pb}=208)$
(a) $4 \times 10^{-4} \mathrm{~g}$
(b) $2.67 \times 10^{-4} \mathrm{~g}$
(c) $2 \times 10^{-4} \mathrm{~g}$
(d) $4.16 \times 10^{-3} \mathrm{~g}$

Hunza Gilgit
Hunza Gilgit
Numerade Educator
03:33

Problem 110

An aqueous solution of a metal bromide $\mathrm{MBr}_{2}(0.04 \mathrm{M})$ is saturated with $\mathrm{H}_{2} \mathrm{~S}$.
What is the minimum $\mathrm{pH}$ at which MS will precipitate? $K_{\mathrm{sp}}$ for $\mathrm{MS}=6.0 \times 10^{-21}$; concentration of saturated $\mathrm{H}_{2} \mathrm{~S}=0.1 \mathrm{M}$ $K_{1}=10^{-7}$ and $K_{2}=1.5 \times 10^{-13}$ for $\mathrm{H}_{2} \mathrm{~S}$.
(a) $1.0$
(b) $1.3$
(c) $13.0$
(d) $0.7$

Rikhil Makwana
Rikhil Makwana
Numerade Educator
18:40

Problem 111

An amount of $0.1$ millimole of $\mathrm{CdSO}_{4}$ is present in $10 \mathrm{ml}$ acid solution of $0.08 \mathrm{M}$ $-\mathrm{HCl}$. Now $\mathrm{H}_{2} \mathrm{~S}$ is passed to precipitate all the $\mathrm{Cd}^{2+}$ ions. What would be the $\mathrm{pH}$ of solution after filtering off precipitate, boiling off $\mathrm{H}_{2} \mathrm{~S}$ and making the solution $100 \mathrm{ml}$ by adding water?
(a) $3.0$
(b) $2.0$
(c) $4.0$
(d) $2.22$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:30

Problem 112

A solution contains a mixture of $\mathrm{Ag}^{+}$ $(0.10 \mathrm{M})$ and $\mathrm{Hg}_{2}^{2+}(0.10 \mathrm{M})$, which are
to be separated by selective precipitation. Calculate the maximum concentration of iodide ion at which one of them gets precipitated almost completely. What per cent of that metal ion is precipitated, before the start of precipitation of second metal ion? $K_{\mathrm{sp}}(\mathrm{AgI})=8.5 \times 10^{-17}$ and
$K_{\mathrm{sp}}\left(\mathrm{Hg}_{2} \mathrm{I}_{2}\right)=2.5 \times 10^{-26}$
(a) $5 \times 10^{-13} \mathrm{M}, 99.83 \%$
(b) $8.5 \times 10^{-16} \mathrm{M}, 99.83 \%$
(c) $2.5 \times 10^{-25} \mathrm{M}, 100 \%$
(d) $5 \times 10^{-13} \mathrm{M}, 98.3 \%$

Lottie Adams
Lottie Adams
Numerade Educator
03:55

Problem 113

The solubility of $\mathrm{CaCO}_{3}$ is $7 \mathrm{mg} /$ litre. Calculate the solubility product of $\mathrm{BaCO}_{3}$ from this information and from the fact that when $\mathrm{Na}_{2} \mathrm{CO}_{3}$ is added slowly to a solution containing equimolar concentration of $\mathrm{Ca}^{2+}$ and $\mathrm{Ba}^{2+}$, no precipitate of $\mathrm{CaCO}_{3}$ is formed until $90 \%$ of $\mathrm{Ba}^{2+}$ has been precipitated as $\mathrm{BaCO}_{3}$.
(a) $4.9 \times 10^{-8}$
(b) $4.9 \times 10^{-9}$
(c) $4.9 \times 10^{-10}$
(d) $7 \times 10^{-4}$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:15

Problem 114

Small amount of freshly precipitated $\begin{array}{llll}\text { magnesium } & \text { hydroxides } & \text { are } & \text { stirred }\end{array}$ vigorously in a buffer solution containing $0.25 \mathrm{M}$ of $\mathrm{NH}_{4} \mathrm{Cl}$ and $0.05 \mathrm{M}$ of $\mathrm{NH}_{4} \mathrm{OH}$.
$\left[\mathrm{Mg}^{2}\right]$ in the resulting solution is $\left(K_{\mathrm{b}}\right.$ for $\mathrm{NH}_{4} \mathrm{OH}=2.0 \times 10^{-5}$ and $K_{\mathrm{sp}}$ of $\mathrm{Mg}(\mathrm{OH})_{2}$
$\left.=8.0 \times 10^{-12}\right)$
(a) $4 \times 10^{-6} \mathrm{M}$
(b) $2 \times 10^{-6} \mathrm{M}$
(c) $0.5 \mathrm{M}$
(d) $2.0 \mathrm{M}$

Lottie Adams
Lottie Adams
Numerade Educator
03:07

Problem 115

The solubility of metal sulphide in saturated solution of $\mathrm{H}_{2} \mathrm{~S}$ (concentration $=0.1 \mathrm{M}$ ) can be represented as:
$\mathrm{MS}(\mathrm{s})+2 \mathrm{H}^{+}(\mathrm{aq}) \rightleftharpoons \mathrm{M}^{2+}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{~S}(\mathrm{aq})$
$K_{\mathrm{eq}}=\frac{\left[\mathrm{M}^{2+}\right]\left[\mathrm{H}_{2} \mathrm{~S}\right]}{\left[\mathrm{H}^{+}\right]^{2}}$
The values of $K_{\mathrm{eq}}$ for the metal sulphides, $\mathrm{MnS}, \mathrm{ZnS}, \mathrm{CoS}$ and $\mathrm{PbS}$ are $3 \times 10^{10}$
$3 \times 10^{-2}, 3$ and $3 \times 10^{-7}$, respectively. If the concentration of each metal ion in a saturated solution of $\mathrm{H}_{2} \mathrm{~S}$ is $0.01 \mathrm{M}$, which metal sulphide(s) will precipitate at $\left[\mathrm{H}^{+}\right]=1.0 \mathrm{M} ?$
(a) $\mathrm{MnS}, \mathrm{ZnS}, \mathrm{CoS}$
(b) $\mathrm{PbS}$
(c) $\mathrm{PbS}, \mathrm{ZnS}, \mathrm{CoS}$
(d) $\mathrm{PbS}, \mathrm{ZnS}$

Aadit Sharma
Aadit Sharma
Numerade Educator