Seema Saini Solutions for Chapter: Ionic Equilibrium, Exercise 3: DPP 7.3

 Calculate the $\mathrm{pH} \mathrm{of} 0.1 \mathrm{M} {\mathrm{Na}}_2{\mathrm{HPO}}_4$ and $0.2 \mathrm{M} {\mathrm{NaH}}_2{\mathrm{PO}}_4$  in which ${\mathrm{pK}}_{{\mathrm{a}}_1}, {\mathrm{pK}}_{{\mathrm{a}}_2} \mathrm{and} {\mathrm{pK}}_{{\mathrm{a}}_3}$for orthophosphoric acid   $\left({\mathrm{H}}_3{\mathrm{PO}}_4\right)$ are  $2.2,7.2$ and $12.0$ respectively.

The $\mathrm{pH}$ of $0.1 \mathrm{M}$ solution of the following substances increases in the order

The $\mathrm{pH}$ of which salt is independent of its concentration:

$\left(1\right) \left({\mathrm{CH}}_3\mathrm{COO}\right){\mathrm{C}}_6{\mathrm{H}}_5\mathrm{NH}$

$\left(2\right) {\mathrm{NaH}}_2{\mathrm{PO}}_4$

$\left(3\right) {\mathrm{Na}}_2{\mathrm{HPO}}_4$

$\left(4\right) {\mathrm{NH}}_4\mathrm{CN}$

A weak acid $\mathrm{HX}$ has ${\mathrm{pK}}_{\mathrm{a}}=5$. The percentage  of hydrolysis of $0.1 \mathrm{M}$ solution of salt $\mathrm{NaX}$ is

The standard hydrolysis constant of anilinium acetate ${\mathrm{K}}_{\mathrm{a}}\left({\mathrm{CH}}_3\mathrm{COOH}\right)=1.8\times {10}^{-5}\mathrm{M},{\mathrm{K}}_{\mathrm{b}}\left(\text{ aniline }\right)=4.6\times {10}^{-10}\mathrm{M}$ at $25°\mathrm{C}$ is:

If the equilibrium constant of the reaction of a weak acid $\mathrm{HA}$ with a strong base is ${10}^9$, then the $\mathrm{pH}$ of $0.1 \mathrm{M} \mathrm{NaA}$ is:

Hydrolysis constants of two salts ${\mathrm{K}}_1$ and ${\mathrm{K}}_2$ of weak acids $\mathrm{HA}$ and $\mathrm{HB}$ are ${10}^{-8}$ and ${10}^{-6}$. If the dissociation constant of third acid $\mathrm{HC}$ is ${10}^{-2}$, the order of acidic strengths of three acids will be:

Which of the given statements are correct?