Question

Which of the following is not a conjugate acid-base pair?

• A. $HP{O}_3^{2-},P{O}_3^{3-}$
• B. $H_{2}P{O}_4^{-},HP{O}_4^{2-}$
• C. $H_{2}P{O}_4^{-},H_{3}P{O}_4$
• D. $H_{2}P{O}_4^{-},P{O}_3^{3-}$

Answer 1

Answer: (D)

$Aci{d}_1+Bas{e}_2\rightleftharpoons Aci{d}_2+Bas{e}_1$
$HP{O}_3^{2-}+H_{2}O\rightleftharpoons H_3{O}^{+}+P{O}_3^{3-}$
$H_{2}P{O}_4^{-}+H_{2}O\rightleftharpoons H_3{O}^{+}+HP{O}_4^{2-}$
$H_{3}P{O}_4+H_{2}O\rightleftharpoons H_3{O}^{+}+H_{2}P{O}_4^{-}$