Assertion : Weak acids have very strong conjugate bases while strong acids have weak conjugate bases

Question

Assertion : Weak acids have very strong conjugate bases while strong acids have weak conjugate bases.\ Reason : Conjugate acid-base pair differ only by one proton.

Professor PC Thomas Classes · Answer

(b) : Strong acids such as perchloric acid $\left(\mathrm{HClO}_4\right)$, hydrochloric acid ( HCl ) give conjugate base ions $\mathrm{ClO}_4^{-}, \mathrm{Cl}^{-}$ which are much weaker bases than $\mathrm{H}_2 \mathrm{O}$. On the other hand, a weak acid like acetic acid is only partially dissociated in aqueous medium and thus the solution mainly contains undissociated acetic acid which proves that $\mathrm{CH}_3 \mathrm{COO}^{-}$is stronger base than $\mathrm{H}_2 \mathrm{O}$.