Introduction and Degree of Hydrolysis

Q. The correct relation between hydrolysis constant ($K_a$) and degree of hydrolysis (h) for the following equilibrium is:
$C{H}_{3}CO{O}^{-}+H_{2}O\stackrel{hydrolysis}{\rightleftharpoons }C{H}_{3}COOH+O{H}^{-}$

1. $h=\sqrt{\frac{K_w\cdot C}{K_a}}$
2. $h=\sqrt{\frac{K_w}{K_a\cdot C}}$
3. $h=\sqrt{\frac{K_a\cdot C}{K_w}}$
4. $h=\sqrt{\frac{K_a}{K_w\cdot C}}$

Q. Calculate the $pH$ of $0.1\text{M}$ $N{H}_{4}Cl$ solution in water :
$K_b\left(N{H}_{4}OH\right)=1.8\times {10}^{-5},log1.8=0.25$

1. $4.5$
2. $7.63$
3. $6.53$
4. $5.13$

Q. The $pH$ of a $0.02MN{H}_{4}Cl$ solution will be: $\left[\text{Given}{K}_b\right(N{H}_{4}OH)={10}^{-5}\text{and log}2=0.301].$

1. $4.65$
2. $5.35$
3. $4.35$
4. $2.65$

Q.

The ${p{K}_a}^o$of acetylsalicyclic acid (aspirin) is 3.5. The pH of gastric juice in the human stomach is about 2 to 3 and the pH in small intestine is about 8. Aspirin will be

1. ionized in the stomach and almost unionized in the small intestine

2. unionized in the small intestine and in the stomach

3. completely ionized in the small intenstine and in the stomach

4. ionized in the small intenstine and almost unionized in the stomach

Q. If $p{K}_b$ for the fluoride ion at ${25}^{\circ }C$ is 10.83, the ionization constant of hydrofluoric acid in water at this temperature is

1. $3.52\times {10}^{-3}$
2. $6.76\times {10}^{-4}$
3. $5.38\times {10}^{-2}$
4. $1.74\times {10}^{-5}$

Q. The $pH$ of $0.1M$ solution of aniline is $8.8$. Its $p{K}_b$ value will be:

1. $7.82$
2. $6.18$
3. $9.40$
4. $8.40$

Q.

An acid Solution of pH = $6$ is diluted $1000$ times, and the pH of the final solution becomes

Q.

Ionization constants of weak acid HA and weak base BOH are $3.0\times {10}^{-7}$ each at 298 K. The percent degree of hydrolysis of their salt at the dilution of 10 L is :

1. 50

2. 25

3. 75

4. 40

Q.

Which of the following will have highest pH ?

1. $0.1MN{H}_{4}N{O}_3$

2. $0.1MN{H}_{4}Br$

3. $0.1M\left(N{H}_4\right)S{O}_4$

4. $0.1M(N{H}_4{)}_{3}P{O}_4$

Q. A crystalline hydrated salt on being rendered anhydrous, loses 45.6% of its weight. The percentage composition of anhydrous salt is : Al = 10.5%, K = 15.1%, S = 24.8% and I = 49.6%. Find the empirical formula of the salt.

1. $KAl{S}_{2}I$
2. $K_{2}Al{S}_{2}I$
3. $KAl{S}_{2}I.12H_{2}O$
4. $K_{2}Al{S}_{2}I.12H_{2}O$

Q. Hydrolysis constant of $N{H}_4^{+}$ is $5.55\times {10}^{-10}.$ Calculate the ionisation constant of $N{H}_4^{+}$.

1. $5.55\times {10}^{-10}$
2. $5.55\times {10}^{-5}$
3. $1.88\times {10}^{-10}$
4. $1.88\times {10}^{-4}$

Q. $K_1$ and $K_2$ for oxalic acid $C_2{H}_2{O}_4$ are $6.5\times {10}^{-2}$ and $6.1\times {10}^{-5}$ respectively. What will be $\left[O{H}^{-}\right]$ in a 0.01 M solution of sodium oxalate?

1. $9.6\times {10}^{-16}$
2. $1.4\times {10}^{-1}$
3. $1.26\times {10}^{-6}$
4. $3.3\times {10}^{-9}$

Q. Sucrose hydrolysis in acid solution into glucose and fructose following first order rate law with a half-life of $3.3\text{h}$ at ${25}^{o}C$. After $9\text{h}$, the fraction of sucrose remaining is $f$. The value of $\log \frac{1}{f}$ is $\times {10}^{-2}$. (Round off to the nearest integer).
[Assume: $\ln 10=2.303,\ln 2=0.693$]

Q. The dissociation constants of two acids $H{A}_1$ and $H{A}_2$ with equal concentrations are $3\times {10}^{-4}$ and $1.8\times {10}^{-5}$ respectively. The relative strength of the acids will be :

1. $1:16$
2. $16:1$
3. $1:4$
4. $4:1$

Q. Calculate the pH of a solution which is ${10}^{-1}MinHCland{10}^{-3}MinC{H}_{3}COOH[K_a=2\times {10}^{-3}]$

1. 2
2. 4
3. 1
4. 3

Q. What is the $pH$ of $0.01MNaHC{O}_3$ ?
Given : $K_{a_1}and{K}_{a_2}$ for $H_{2}C{O}_3$ are $4.5\times {10}^{-7}and4.7\times {10}^{-11}$ respectively at $25{}^{o}C$.

1. 8.33
2. 10.57
3. 6.33
4. 5.66

Q. Hydrolysis constant of $N{H}_4^{+}$ is $5.55\times {10}^{-10}.$ Calculate the ionisation constant of $N{H}_4^{+}$.

1. $5.55\times {10}^{-5}$
2. $5.55\times {10}^{-10}$
3. $1.88\times {10}^{-10}$
4. $1.88\times {10}^{-4}$

Q. Given below are two statements:
Statement I ; Both $CaC{l}_2\cdot 6H_{2}OandMgC{l}_2\cdot 8H_{2}O$
undergo dehydration on heating.

Statement II : BeO is amphoteric whereas the oxides of other elements in the same group are acidic.

In the light of the above statements, choose the correct answer fromm the options given below.

1. Statement I is false but statement II is true
2. Both statement I annd statement II are true
3. Both statement I and statement II are false
4. Statement I is true but statement II is false

Q.

What is the pH of the solution which is twice alkaline as that of pure water at ${25}^{\circ }C$ ?

1. 4.3

2. 7.3

3. 8.9

4. 12.6

Q.

The solution left after the reaction of Sodium with water is alkaline.

1. True
2. False

Q.

In a pseudo first order hydrolysis of ester in water, the following results were obtained:
$\begin{array}{ccccc}t/s& 0& 30& 60& 90\\ \left[Ester\right]/mol{L}^{-1}& 0.55& 0.31& 0.17& 0.085\end{array}$
Calculate the average rate of reaction between the time interval 30 to 60 s.

$\begin{array}{ccccc}t/s& 0& 30& 60& 90\\ \left[Ester\right]/mol{L}^{-1}& 0.55& 0.31& 0.17& 0.085\end{array}$
Calculate the psuedo first order rate constant for the hydrolysis of ester.

Q. Choose the correct statement(s) for an aqueous solution of $N{a}_{2}C{O}_3$.

1. The solution will be basic in nature
2. The solution will be acidic in nature.
3. Cationic $\left(N{a}^{+}\right)$ hydrolysis occurs.
4. Anionic $\left(C{O}_3^{2-}\right)$ hydrolysis occurs

Q. For a weak acid, the incorrect statement is:

1. its dissociation constant is low
   
2. its $p{K}_a$ is very low
   
3. it is partially dissociated
4. solution of its sodium salt is alkaline in water

Q. For a ammonium chloride solution in water, the given equilibrium reaction occur:
$N{H}_4^{+}\left(aq\right)+H_{2}O\left(l\right)\stackrel{hydrolysis}{\rightleftharpoons }N{H}_{4}OH\left(aq\right)+H^{+}\left(aq\right)$
Which of the following describes correct relation ?

1. $K_h=K_w\times K_b$
2. $K_h=\frac{K_b}{K_w}$
3. $K_h=\frac{K_w}{K_b}$
4. None of the above

Q. Four solutions of $N{H}_{4}Cl$ are taken with concentrations $1M,0.1M,0.01Mand0.001M$. Their degree of hydrolysis are $h_1,h_2,h_3$ and $h_4$. What is the decreasing order of degree of hydrolysis ?

1. $h_1>h_2>h_3>h_4$
2. $h_1=h_2=h_3=h_4$
3. $h_4>h_3>h_2>h_1$
4. $\text{None of these}$

Q. The $pH$ of a $0.02\text{M}N{H}_{4}Cl$ solution will be:
[Given: $K_b\left(N{H}_{4}OH\right)={10}^{-5}$ and $\log 2=0.301$]

1. $4.65$
2. $5.35$
3. $4.35$
4. $2.65$

Q. Which of the following salts will give highest pH in water?
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AIPMT 2014

1. $NaCl$
2. $KCl$
3. $CuS{O}_4$
4. $N{a}_{2}C{O}_3$

Q. Choose the correct statement(s) for an aqueous solution of $N{a}_{2}C{O}_3$.

1. The solution will be basic in nature
2. The solution will be acidic in nature.
3. Cationic $\left(N{a}^{+}\right)$ hydrolysis occurs.
4. Anionic $\left(C{O}_3^{2-}\right)$ hydrolysis occurs

Q. If $K_a=1.8\times {10}^{-5}$, calculate the degree of hydrolysis of 0$.1M$ solution of sodium acetate at ${25}^{\circ }C$:

1. $7.45\times {10}^{-5}$
2. $7.45\times {10}^{-3}$
3. $7.45\times {10}^{-1}$
4. $5.5\times {10}^{-2}$

Q.

The pH of a sample of vinegar is $3.76$. Calculate the concentration of hydrogen ions in it.