Question

What is the conjugate base of bisulfate ion $HS{O_3}^ -$ ?

Answer 1

A substance's conjugate base is just the parent substance minus one proton, while its conjugate acid is the parent substance plus one proton. Any compound of the general formula ${X^{n + }}$ can be transformed into a conjugate base $H{X^{{{(n + 1)}^ - }}}$ by the loss of one proton.

Complete answer:
A conjugate base is a basic member, ${X^ - }$ , of a pair of two molecules that convert into each other by gain or loss of a proton in the Bronsted-Lowry (protonic) theory of acids and bases. The acid produced $HX$ is called conjugate acid.The hydrogen sulfite ion $HS{O_3}^ -$ is amphiprotic. If it can both donate or accept a proton, thus acting either like an acid or a base (according to Brønsted-Lowry's theory of acids and bases: acids are proton donors and bases are proton acceptors).
When $S{O_2}$ is dissolved in water, the following is produced
${H_2}O(l)$ $+$ $S{O_2}(g)$ $\to$ ${H^ + }(aq)$ $+$ $HS{O_3}^{^ - }(aq)$ .
Now we want the conjugate base of $HS{O_3}^ -$ (note this is a negatively charged ion)
$HS{O_3}^ -$ $(aq)$ $\to$ ${H^ + }(aq)$ + $S{O_3}^{2 - }$ .
The $2 -$ charged sulfite ion is the conjugate base of The $1 -$ charge hydrogen sulfite ion.
Since we are trying to find the conjugate base, we must subtract $1$ hydrogen ions.
$HS{O_3}^ - {H^ + }$ = S{O_3}^\\_ (charge is $- 1$ ).

Note:
The formula of the conjugate base is the formula of the acid less one hydrogen. The reacting base becomes its conjugate acid. The formula of the conjugate acid is the formula of the base plus one hydrogen ion. A conjugate base is a species created by removing a proton from acid and gaining a hydrogen ion in the reverse process.
The general scheme for a Bronsted-Lowry acid/base reaction can be visualized in the form:
$Acid + base$ $\rightleftarrows$ $conjugate$ $base$ $+$ $Conjugate$ $acid$ .