Which Of The Following Is The Conjugate Acid Of ${\mathrm{SO}}_4^{2-}$?

The correct option is C

${\mathrm{HSO}}_4^{-}$

The explanation for correct option

(c) ${\mathrm{HSO}}_4^{-}$

• The Bronsted- Lowry theory is of acid and base reaction.
• According to it, an acid can donate a proton, namely a hydrogen ion.
• And base can accept that hydrogen ion and for that, it must have electron lone pair on the base which will bond to that hydrogen ion.
• Bronsted- Lowry base's conjugate acid is that chemical species that is formed after having the hydrogen ion accepted by the base as a proton.
• Using this concept, we find the conjugate acid of ${\mathrm{SO}}_4^{2-}$, we get the following conjugate acid.,

${\mathrm{SO}}_4^{2-}+{\mathrm{H}}^{+}\to {\mathrm{HSO}}_4^{-}$

• Hence the correct option is (c) ${\mathrm{HSO}}_4^{-}$.

The explanation for incorrect options

(a) ${\mathrm{H}}^{+}$

• By using the Bronsted- Lowry concept, it is clear that ${\mathrm{H}}^{+}$ is not the correct option
• Hence, (a) ${\mathrm{H}}^{+}$is incorrect.

(b) ${\mathrm{SO}}_4^{2-}$

• By using the Bronsted- Lowry concept, it is clear that ${\mathrm{SO}}_4^{2-}$ is not the correct option
• Hence, (b) ${\mathrm{SO}}_4^{2-}$ is incorrect.

(d) ${\mathrm{H}}_2{\mathrm{SO}}_4$

• By using the Bronsted- Lowry concept, it is clear that ${\mathrm{H}}_2{\mathrm{SO}}_4$ is not the correct option
• Hence, (d) ${\mathrm{H}}_2{\mathrm{SO}}_4$ is incorrect.

Hence, the correct option is (c) ${\mathrm{HSO}}_4^{-}$