Identify each species in the following equilibrium according to the code: $SA = \text{stronger acid}$; $SB = \text{stronger base}$; $WA = \text{weaker acid}$; $WB = \text{weaker base}$. The $pK_a$ of $(CH_3)_2NH_2^+$ is $10.7$ (conjugate acid of $(CH_3)_2NH$) and the $pK_a$ of $CH_3OH$ is $15.2$.
$CH_3OH$ $(1)$ + $(CH_3)_2NH$ $(2)$ $\rightleftarrows CH_3O^- + (CH_3)_2NH_2^+$

When $HClO_4$ is dissolved in the weak acid $HF$,the following equilibrium is established:
$HF + HClO_4 \rightleftharpoons H_2F^+ + ClO_4^-$
Which of the following is the correct set of conjugate acid-base pairs?

In the following reaction $HCO_3^{-} + H_2O \rightleftharpoons CO_3^{2-} + H_3O^{+}$,which two substances are Bronsted bases?

Phosphoric acid ionizes in three steps with their ionization constant values $K_{a_1}, K_{a_2}$ and $K_{a_3}$ respectively,while $K$ is the overall ionization constant. Which of the following statements are true?
$A.$ $\log K = \log K_{a_1} + \log K_{a_2} + \log K_{a_3}$
$B.$ $H_3PO_4$ is a stronger acid than $H_2PO_4^{-}$ and $HPO_4^{2-}$
$C.$ $K_{a_1} > K_{a_2} > K_{a_3}$
$D.$ $K_{a_1} = \frac{K_{a_3} + K_{a_2}}{2}$
Choose the correct answer from the options given below

The conjugate acid of $S_2O_8^{2-}$ is

Which of the following species is an acid and also a conjugate base of another acid?