Question

Hydrogen sulfate reacts with water to produce sulfate ions and hydronium ions: hso4−+h2o⇌so42−+h3o+ identify the conjugate acid-base pairs.

Answer 1

The generic equation for a reaction between an acid and water is 

     $HX_{(aq)} + H_{2}O_{(aq)} --> X_{(aq)}^{-} + H_{3}O_{(aq)}^+$

When an acid "reacts" with water, water acts as the base that accepts the proton (H+) from the acid. The remaining ion that is formed after the acid has donated its proton is called the conjugate base ($X^-$), and the conjugate acid-base pair is $HX$ - $X^-$. 

Hydrogen sulfate ($HSO_{4}^-$) is an ion from sulfuric acid. It is still an acid in itself and can "react" with water (($H_{2}O$) to form the sulfate ($SO_{4}^2-$) and hydronium ($H_{3}O^+$)ions. 

$HSO_{4(aq)}^{-} + H_{2}O_{(aq)} --> SO_{4(aq)}^{2-} + H_{3}O_{(aq)}^+$

Based on the previous discussion, $SO_{4(aq)}^2-$ is identified to be the conjugate of the acid $HSO_{4(aq)}^-$. Thus, the conjugate acid-base pair is $HSO_{4(aq)}^{-} - SO_{4(aq)}^{2-}$.