Ostwald Dilution Law Mathematical Interpretation

Q.

At ${25}^{\circ }C$, the dissociation constant of a base BOH is $1.0\times {10}^{-12}$. The

concentration of Hydroxyl ions in 0.01 M aqueous solution of the base

would be

1. 2.0 x 10^-6 mol L^-1

2. 1.0 x 10^-5 mol L^-1

3. 1.0 x 10^-6 mol L^-1

4. 1.0 x 10^-7 mol L^-1

Q. Calculate the $pH$ of $0.01\text{M}{H}_{2}S{O}_4$.

1. $2$
2. $2.3$
3. $1.7$
4. $0.3$

Q. The pH of a solution obtained by mixing $50mL$ of $1MHCl$ and $30mL$ of $1MNaOH$ is $x\times {10}^{-4}$. The value of x is ______(Nearest intger). [log2.5=0.3979]

Q.

A monoprotic acid in 1.00 M solution is 0.01% ionised. The dissociation constant of this acid is

1. 1 X 10^-8

2. 1 X 10^-4

3. 1 X 10^-6

4. 1 X 10^-5

Q.

It has been found that the pH of a 0.01M solution of an organic acid is 4.15. Calculate the concentration of the anion, the ionization constant of the acid and its pKa.

Q. Dilution processes of different aqueous solution, with water, are given in LIST-I. The effects of dilution of the solutions on $\left[H^{+}\right]$ are given in LIST -II.
(Note: Degree of dissociation $\left(\alpha \right)$ of weak acid and weak base is << 1; degree of hydrolysis of salt << 1; $\left[H^{+}\right]$ represents the concentration of $H^{+}$ ions)
$\begin{array}{cc}\text{LIST -I}& \text{LIST-II}\\ \text{P. 10 mL of 0.1 M NaOH +20 mL of}& \text{1. The value of}\left[H^{+}\right]\text{does not}\\ \text{0.1 M acetic acid diluted to 60 mL}& \text{change on dilution}\\ \text{Q. 20 mL of 0.1 M NaOH +20 mL of}& \text{2. The value of}\left[H^{+}\right]\text{changes to half}\\ \text{0.1 M acetic acid diluted to 80 mL}& \text{of its initial value on dilution}\\ \text{R. 20 mL of 0.1 M HCl + 20 mL of 0.1}& \text{3. The value of}\left[H^{+}\right]\text{changes to two}\\ \text{M ammonia solution diluted to 80 mL}& \text{times of its initial value on dilution}\\ \text{S. 10 mL saturated solution of}Ni(OH{)}_2& \text{4. The value of}\left[H^{+}\right]\text{changes to}\frac{1}{\sqrt{2}}\\ \text{in equilibrium with excess solid}Ni(OH{)}_2& \text{times of its initial value on dilution}\\ \text{is diluted to 20 mL (solid}Ni(OH{)}_2\text{is still}& \\ \text{present after dilution).}& \\ & \text{5. The value of}\left[H^{+}\right]\text{changes to}\sqrt{2}\\ & \text{times of its initial value on dilution}\end{array}$
Match each process given in LIST -I with one or more effect(s) in LIST -II. The correct option is

1. $P\to 4;Q\to 3;R\to 2;S\to 3$
2. $P\to 1;Q\to 4;R\to 5;S\to 3$
3. $P\to 4;Q\to 2;R\to 3;S\to 1$
4. $P\to 1;Q\to 5;R\to 4;S\to 1$

Q. Accumulation of lactic acid $\left(H{C}_3{H}_5{O}_3\right),$ a monobasic acid in tissues leads to pain and a feeling of fatigue. In a 0.10 M aqueous solution, lactic acid is 3.7% dissociates. The value of dissociation constant, $K_a,$ for this acid will be

1. $1.4\times {10}^{-4}$
2. $1.4\times {10}^{-5}$
3. $3.7\times {10}^{-4}$
4. $2.8\times {10}^{-4}$

Q.

What Is the pH Of Nucleic Acid?

Q. What will be the $pH$ and $\%\alpha$ (degree of hydrolysis) respectively for the salt of weak acid and weak base $\left(BA\right)$ of $0.1M$ concentration?
Given : $K_a$ for $HA={10}^{-6}$ and $K_b$ for $BOH={10}^{-6}$

1. $5,1\%$
2. $7,10\%$
3. $9,0.01\%$
4. $7,0.01\%$

Q.

0.1 mole of HCl is added to 2 litres of buffer solution. The decreases in pH of that buffer by 0.5. Then the buffer capacity is

1. 0.5

2. 0.2

3. 0.1

4. 2

Q. Caculate pH of resultant solution of $0.1MHA+0.1MHB$
$\left[K_a\right(HA)=2\times {10}^{-5};K_a(HB)=4\times {10}^{-5}]$
log(2.44)=0.387
$\sqrt{6}=2.44$

1. 2.61
2. 4.56
3. 3.49
4. 1.02

Q.

pH of two solutions :
I. 50 ml of 0.2 M~HCl + 50 ml of 0.2 M HA $(K_a=1.0\times {10}^{-5})$ and
II. 50 ml of 0.2 M HCl + 50 ml of 0.2 M NaA will be respectively

1. 3 and 1

2. 0.70 and 2.85

3. 1 and 2.85

4. 1 and 3

Q. Calculate the $H^{+}$ ion concentration of a 0.01 N weak monobasic acid. The value of dissociation constant is $4.0\times {10}^{-10}$.

1. $2\times {10}^{-6}mole{L}^{-1}$
2. $2\times {10}^{-5}mole{L}^{-1}$
3. $3\times {10}^{-6}mole{L}^{-1}$
4. $3\times {10}^{-5}mole{L}^{-1}$

Q.

A monoprotic acid in 1.00 M solution is 0.01% ionised. The dissociation constant of this acid is

1. $1\times {10}^{-8}$

2. $1\times {10}^{-4}$

3. $1\times {10}^{-6}$

4. $1\times {10}^{-5}$

Q.

The dissociation constant of two acids $H{A}_1$ and $H{A}_2$ are $3.14\times {10}^{-4}$ and $1.96\times {10}^{-5}$ respectively. The relative strength of the acids will be approximately

1. 1:4

2. 4:1

3. 1:16

4. 16:1

Q. $5mL$ of $NHCl,20mL$ of $N/2H_{2}S{O}_4$ and $30mL$ of $N/3HN{O}_3$ are mixed together and volume made to $1L$.

1. $N/5$
2. $N/10$
3. $N/20$
4. $N/40$

Q. The normality of solution obtained by mixing $10ml$ of $N/5HCl$ and $30ml$ of $N/10HCl$ is:

1. $\frac{N}{7.5}$
2. $\frac{N}{15}$
3. $\frac{N}{5}$
4. $\frac{N}{8}$

Q. ${Cl}^{-}$ is _____ (stronger/weaker) base than ${Br}^{-}$.

Q. The $\left[H^{+}\right]$ of a resulting solution that is $0.01$M acetic acid $(K_a=1.8\times {10}^{-5})$ and $0.01$M in benzoic acid $(K_a=6.3\times {10}^{-5})$:

1. $2.8\times {10}^{-3}$
2. $9\times {10}^{-5}$
3. $9\times {10}^{-4}$
4. $81\times {10}^{-4}$

Q.

At ${25}^{\circ }C$, the dissociation constant of a base BOH is $1.0\times {10}^{-12}$. The

concentration of Hydroxyl ions in 0.01 M aqueous solution of the base

would be

1. $2.0\times {10}^{-6}mol{L}^{-1}$

2. $1.0\times {10}^{-5}mol{L}^{-1}$

3. $1.0\times {10}^{-6}mol{L}^{-1}$

4. $1.0\times {10}^{-7}mol{L}^{-1}$

Q. The volume of water to be added to 200 mL of seminormal $HCl$ solution to make it decinormal is:

1. 200 mL
2. 600 mL
3. 400 mL
4. 800 mL

Q. The van't hoff factor for a very dilute solution of ${Fe}_2{\left({SO}_4\right)}_3$ is:

1. $9$
2. $5$
3. $24$
4. $16$

Q. $100mL$ of $0.5N$ $NaOH$ were added to $20ml$ of $1N$ $HCl$ and $10mL$ of $3N$ $H_2{SO}_4$. The solution is :

1. basic
2. none of these
3. neutral
4. acidic

Q.

At ${25}^{\circ }C$, the dissociation constant of a base BOH is $1.0\times {10}^{-12}$. The

concentration of Hydroxyl ions in 0.01 M aqueous solution of the base

would be

1. $2.0\times {10}^{-6}mol{L}^{-1}$

2. $1.0\times {10}^{-5}mol{L}^{-1}$

3. $1.0\times {10}^{-6}mol{L}^{-1}$

4. $1.0\times {10}^{-7}mol{L}^{-1}$

Q. Explain Ostwald's dilution law.

Q.

The dissociation constant of two acids $H{A}_1$ and $H{A}_2$ are $3.14\times {10}^{-4}$ and $1.96\times {10}^{-5}$ respectively. The relative strength of the acids will be approximately

1. 1:4

2. 4:1

3. 1:16

4. 16:1

Q. The pH of two equimolar weak acids are 3.0 and 5.0 respectively. Their relative strength is :

1. 3:5
2. 5:3
3. 100:1
4. 1:100

Q. The dissociation constants of two acids $H{A}_1$ and $H{A}_2$ are $3.0\times {10}^{-4}$ and $1.8\times {10}^{-5}$ respectively. The relative strengths of the acids will be approximately

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

Q. $1.6g$ of pyrolusite ore was treated with $50c{m}^3$ of $1.0N$ oxalic acid and some sulphuric acid. The oxalic acid left undecomposed was raised to $250c{m}^3$ in a flask. $25c{m}^3$ of this solution when titrated with $0.1NKMn{O}_4$ required $32c{m}^3$ of the solution. Find the percentage of pure $Mn{O}_2$ in the sample and also the percentage of available oxygen.

Q. Degree of dissociation of 0.1 N $C{H}_{3}COOH$ is:
[Dissociation constant is 1 $\times {10}^{-5}$]

1. ${10}^{-5}$
2. ${10}^{-4}$
3. ${10}^{-3}$
4. ${10}^{-2}$