Which of the following may act as buffer in aqueous solution? — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

A buffer consists of a weak acid and its conjugate base, or a weak base and its conjugate acid. (A) is a weak base ($\text{NH}_4\text{OH}$) with its conjugate acid salt ($\text{NH}_4\text{Cl}$). (B) is a weak acid ($\text{CH}_3\text{COOH}$) with its conjugate base salt ($\text{CH}_3\text{COONa}$). (D) Borax and boric acid form a well-known buffer system in aqueous solution. (C) consists of a weak acid salt and a neutral strong electrolyte, lacking the weak acid component needed to act as a buffer. Therefore, correct answer is A,B,D.