Question

Which pair is a Brønsted–Lowry conjugate acid–base pair? `NH_3 ; NH_4^+` or `H_3O^+ ; OH^-` or `HCl; HBr` or `ClO_4^(-); ClO_3^-`

Answer 1

The Brønsted–Lowry theory is an acid–base reaction theory. The fundamental concept of this theory is that when an acid and a base react with each other, the acid forms its conjugate base, and the base forms its conjugate acid by exchange of a proton.

So the anwer could only be the first pair: `NH_3` and ammonium catione.