Ostwald Dilution Law

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

1. $2\times {10}^{-4}$$mol{L}^{-1}$
2. $2\times {10}^{-8}$ $mol{L}^{-1}$
3. $2\times {10}^{-2}$ $mol{L}^{-1}$
4. $2\times {10}^{-6}$ $mol{L}^{-1}$

Q. What will be the new $pH$ if $0.01mol$ of $NaOH$ is added to a $1L$ buffer solution that is $0.1M$ in acetic acid $\left(C{H}_{3}COOH\right)$ and $0.1M$ in sodium acetate $\left(C{H}_{3}COONa\right)$ ?
Dissociation constant $K_a$ of acetic acid at ${25}^{\circ }C$ is $1.8\times {10}^{-5}$

1. 5.52
2. 4.92
3. 6.13
4. 4.1

Q. The dissociation constant for a weak monobasic acid is $4\times {10}^{-10}.pH$ for this $0.01N$ weak monobasic acid is :

1. 9.7
2. 1.7
3. 3.7
4. 5.7

Q.

The best indicator for titrating HCl with ammonium hydroxide is

1. litmus

2. phenolphthalein

3. methyl orange

4. phenol red

Q. Select the correct statement about Ostwald's dilution law :

1. It is valid for weak electrolytes dissociation.
2. It is useful in calculating ionisation constant of acids or bases.
3. All of the above
4. It is not valid for strong electrolytes.

Q. For a hypothetical reaction
$4A+5B\leftrightharpoons 4P+6Q,$
The equilibrium constant $K_c$ has units

1. $mol{L}^{-1}$
2. $mo{l}^{-1}L$
3. $(mol{L}^{-1}{)}^{-2}$
4. unit less
   

Q. Select the correct statement about Ostwald's dilution law :

1. It is valid for weak electrolytes dissociation.
2. It is useful in calculating ionisation constant of acids or bases.
3. It is not valid for strong electrolytes.
4. All of the above

Q.

The equilibrium constant $K_c$ for the reaction $N_2$ (g) + 3$H_2$ (g)$\leftrightharpoons$ 2$N{H}_3$ (g) is:

1. $\frac{\left[2N{H}_3\right]}{\left[N_2\right]\left[3H_2\right]}$

2. $\frac{\left[N{H}_3\right]}{\left[N_2\right]{\left[3H_2\right]}^3}$

3. $\frac{{\left[N{H}_3\right]}^2}{\left[N_2\right]\left[3H_2\right]}$

4. $\frac{{\left[N{H}_3\right]}^2}{\left[N_2\right]{\left[H_2\right]}^3}$

Q. What will be the acidity of Magnesium hydroxide?

1. 1
2. \N
3. 2
4. 3

Q. Calculate $pH$ of $1.0MP{O}_4^{3-}$ in aqueous solution. Given $p{K}_{b}ofP{O}_4^{3-}=1.62$.

1. 13.19
2. 7
3. 6.5
4. 11.5

Q.

Oswalds dilution law is applicable for both weak electrolytes and strong electrolytes- True or False?

1. True

2. False

Q.

If $\alpha$ is the degree of ionization, $C$ the concentration of a weak electrolyte and $K_a$ the acid ionization constant, then the correct relationship between $\alpha$, Cand $K_a$ is

1. ${\alpha }^2=\sqrt{K_a\times C}$.

2. ${\alpha }^2=\sqrt{\frac{C}{K_a}}$

3. $\alpha =\sqrt{\frac{K_a}{C}}$

4. $\alpha =\sqrt{\frac{C}{K_a}}$