In an aqueous buffer, addition of ammonium chloride establishes the equilibrium
HPO42−(aq)+NH4+(aq)⇌H2PO4−(aq)+NH3(aq)
Which statement correctly identifies the Brønsted–Lowry acid–base pairs for this equilibrium?
a) NH3 is the acid with conjugate base NH4+, and H2PO4− is the base with conjugate acid HPO42−.
b) NH4+ is the acid with conjugate base NH3, and HPO42− is the base with conjugate acid H2PO4−.
c) H2PO4− is the acid with conjugate base HPO42−, and NH3 is the base with conjugate acid NH4+.
d) NH4+ is the base with conjugate acid NH3, and HPO42− is the acid with conjugate base H2PO4−.