Chemistry - GOC Question with Solution | TestHub

4-Methylbenzenesulfonic acid ($\mathrm{p}{K}_{\mathrm{a}}$ ≈ -2) is much stronger than carbonic acid ($\mathrm{p}{K}_{\mathrm{a}}$ ≈ 6.4), so it protonates the bicarbonate ion; the carbonic acid formed decomposes and $\mathrm{C}{\mathrm{O}}_2$ gas is evolved.