The conjugate acid of $H_2PO_4^-$ is

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 bases $CN^{-}$,$F^{-}$ and $NO_2^-$ will be:

What is the increasing order of basic strength for $Cl^{-}, CH_3COO^{-}, OH^{-},$ and $F^{-}$?

The dissociation constants of two acids $HA_1$ and $HA_2$ are $3.0 \times 10^{-4}$ and $1.8 \times 10^{-5}$ respectively. The relative strengths of the acids will be

Which of the following can act as an acid and as a base?

When $KHSO_4$ is added into a concentrated solution of $H_2SO_4$,the acidity of the solution