Which of the following form conjugate acid-base pairs in the correct order (Acid first, then Conjuga — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

A conjugate acid-base pair differs by exactly one proton ($H^+$). The acid is the proton donor, and the base is the proton acceptor. (A) $NH_3 \rightarrow H^+ + NH_2^-$ (Correct). (B) $OH^- \rightarrow H^+ + O^{2-}$, so $H_2O$ is the conjugate acid of $OH^-$, not its base (Incorrect order). (C) $HCO_3^- \rightarrow H^+ + CO_3^{2-}$ (Correct). (D) $H_3O^+ \rightarrow H^+ + H_2O$ (Correct).