I know that according to Brönsted-Lowry theory, a base is a proton acceptor while an acid is a proton donor. Also, the acid-base pair that differs by a single proton is a conjugate pair.
If this is true, then the sodium ion is a conjugate acid of sodium hydroxide. But if we look at $\ce{Na^+}$ itself, we find that it cannot donate a proton. Someone in the comments under this answer suggested that in its hydrated state, $\ce{Na^+}$ can act as a Brönsted-Lowry acid. How?