Which is the strongest of the following acids?

The successive equilibrium constants for the stepwise dissociation of a tribasic acid are $K_1$, $K_2$ and $K_3$, respectively. The equilibrium constant for the overall dissociation is

Which are the conjugate bases of the strong acids $HClO_4$,$H_2SO_4$,$HNO_3$,and $HPO_4^{2-}$? Are they strong or weak?

Derive $K_w = K_a \times K_b$ and $pK_w = pK_a + pK_b$ for a weak base $B$ and its conjugate acid $BH^{+}$.

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:

The conjugate acid of $H_2PO_4^-$ is