The relation is true for which of the following pair(s)? — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The relationship $pK_a + pK_b = 14$ holds specifically for Brønsted-Lowry conjugate acid-base pairs in water at $25^\circ\text{C}$. Option A ($\text{MeNH}_3^+$ and $\text{CH}_3\text{NH}_2$) and Option B ($\text{CH}_3\text{COOH}$ and $\text{CH}_3\text{COO}^-$) are both valid conjugate acid-base pairs. Option C is incorrect because the conjugate base of $\text{H}_3\text{O}^+$ is $\text{H}_2\text{O}$, not $\text{OH}^-$. Option D is incorrect as it does not represent a standard conjugate pair. Therefore, correct answer is A,B.