In an aqueous buffer

CHEMISTRY · Single correct · A Level · Chemistry · Acids and bases · Acids and bases

Problem

In an aqueous buffer, addition of ammonium chloride establishes the equilibrium

HPO_4^{2-}(aq)+NH_4^{+}(aq)\rightleftharpoons H_2PO_4^{-}(aq)+NH_3(aq)

Which statement correctly identifies the Brønsted–Lowry acid–base pairs for this equilibrium? (a)

NH_3

is the acid with conjugate base

NH_4^{+}

, and

H_2PO_4^{-}

is the base with conjugate acid

HPO_4^{2-}

. (b)

NH_4^{+}

is the acid with conjugate base

NH_3

, and

HPO_4^{2-}

is the base with conjugate acid

H_2PO_4^{-}

. (c)

H_2PO_4^{-}

is the acid with conjugate base

HPO_4^{2-}

, and

NH_3

is the base with conjugate acid

NH_4^{+}

. (d)

NH_4^{+}

is the base with conjugate acid

NH_3

, and

HPO_4^{2-}

is the acid with conjugate base

H_2PO_4^{-}