Values of dissociation constant, $K_a$ are given as follows

Acid	$K_a$
$HCN$	$6.2\times 10^{-10}$
$HF$	$7.2\times 10^{-4}$
$HNO_2$	$4.0\times 10^{-4}$

Correct order of increasing base strength of the base $CN^-,F^-$ and $NO_2^-$ will be

The ionization constant of $HF$, $HCOOH$ and $HCN$ at $298\, K$ are $6.8 \times 10^{-4}, 1.8 \times 10^{-4}$ and  $4.8 \times 10^{-9}$ respectively. Calculate the ionization constants of the corresponding conjugate base.

Dissociation constat of weak acid $HA$ is $1.8 \times {10^{ - 4}}$ calculate Dissociation constant of its conjugate base ${A^ - }$

The degree of dissociation $(\alpha )$ of $PCl_5$ obeying the equilibrium;  is $PC{l_5}\, \rightleftharpoons \,PC{l_3}\, + \,C{l_2}$ related to the pressure at equlibrium by

The $pH$ of $0.1\, M$ monobasic acid is $4.50$ Calculate the concentration of species $H ^{+},$ $A^{-}$ and $HA$ at equilibrium. Also, determine the value of $K_{a}$ and $pK _{a}$ of the monobasic acid.

Explain ionization and ionization constant in di and polyprotic acid.