$\mathrm{Assertion}:$ Aqueous solutions of all strong acids contain only the same acid, the hydronium ion.

$\mathrm{Reason}:$ Hydronium ion is the strongest acid that can exist in any significant concentration in dilute aqueous solution.

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

Assertion: Acids that have more than one proton that can be donated to base are called polyprotic acids.

Reason: For all dicrotic acids, the equilibrium constant ${\mathrm{K}}_{\mathrm{a}2}$, for the second stage of ionisation is smaller than the equilibrium constant, ${\mathrm{K}}_{\mathrm{a}1}$ for the first stage of ionisation.

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

$\mathrm{Assertion}:$ $0.20\mathrm{M}$ solution of $\mathrm{NaCN}$ is more basic than $0.20\mathrm{M}$ solution of $\mathrm{NaF}$.

$\mathrm{Reason}:$ ${\mathrm{K}}_{\mathrm{a}}$ of $\mathrm{HCN}$ is very much less than that of $\mathrm{HF}$.

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

$\mathrm{Assertion}:$ Addition of $\mathrm{HCl}\left(\mathrm{aq}\right)$ to $\mathrm{HCOOH}\left(\mathrm{aq}\right)$, decrease the ionization of $\mathrm{HCOOH}\left(\mathrm{aq}\right)$

$\mathrm{Reason}:$ Due to common ion effect of ${\mathrm{H}}^{+}$, ionization of $\mathrm{HCOOH}$ decreased.

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

$\mathrm{Assertion}:$ $\mathrm{pH}$ of $\mathrm{x} \mathrm{M} \mathrm{HCl}$ is less than $\mathrm{pH}$. of $\mathrm{x} \mathrm{M} {\mathrm{CH}}_3 \mathrm{COOH}$.
$\mathrm{Reason}:$ The degree of ionization of $\mathrm{HCl}$ and ${\mathrm{CH}}_3\mathrm{COOH}$ are equal at infinite dilution.

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

$\mathrm{Assertion}:$ The conjugate acid base pair differ by a proton.

$\mathrm{Reason}:$ ${\mathrm{NH}}_2^{-}$ and ${\mathrm{NH}}_4^{+}$ are conjugate acid base pair.

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

$\mathrm{Assertion}:$ The degree of dissociation of ${\mathrm{CH}}_3\mathrm{COOH}$ is more in a solution which is basic than in water.
$\mathrm{Reason}:$ ${\mathrm{K}}_{\mathrm{a}}$ of ${\mathrm{CH}}_3\mathrm{COOH}$ increases in basic solution.

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

Assertion: If solubility of ${\mathrm{Ag}}_2{\mathrm{CrO}}_4$, is $\mathrm{S}$ mole/litre, its solubility product will be $S^2$.

Reason: Solubility product of ${\mathrm{Ag}}_2{\mathrm{CrO}}_4$ is given by expression ${\mathrm{K}}_{\mathrm{sp}}=\left[{\mathrm{Ag}}^{+}\right]\left[{\mathrm{CrO}}_4^{2-}\right]$

Directions: Each of these questions contains an Assertion followed by reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

$\mathrm{Assertion}:$ $\mathrm{NaCl}+\mathrm{HCl}$ does not experience common ion effect.

$\mathrm{Reason}:$ $\mathrm{NaCl}$ and $\mathrm{HCl}$ are strong electrolytes.