Question

According to Bronsted-Lowry concept of acids and bases a conjugate acid-base pair can exist as

Mark the option in which conjugate pair is not correctly matched.
Species Conjugate acid Conjugate base

• A. $HCO^{-}_{3}\,\,\,\,\,\,\,CO^{2-}_{3}\,\,\,\,\,H_{2}CO_{3}$
• B. $HPO^{2-}_{4}\,\,\,\,\,\,\,H_{2}PO^{-}_{4}\,\,\,\,\,PO^{3-}_{4}$
• C. $NH_{3}\,\,\,\,\,\,\,NH^{-}_{2}\,\,\,\,\,NH_{4}^{+}$
• D. $HS^{-}\,\,\,\,\,\,\,S^{2-}\,\,\,\,\,H_{2}S$

Answer 1

Answer: (B)

$HPO^{2-}_{4}\,\,\,\,\,\,\,H_{2}PO^{-}_{4}\,\,\,\,\,PO^{3-}_{4}$

Answer 2

Brønsted-Lowry acid-base conjugate pairs differ by just one proton. Brønsted-Lowry acids are proton donors, while Brønsted-Lowry bases are proton acceptors. The conjugate acid of hydrogen phosphate $\text{HPO}_4^{2-}$ is dihydrogen phosphate $\text{H}_2\text{PO}_4^-$, and its conjugate base is phosphate $\text{PO}_4^{3-}$.