# Is sodium aquo complex a Brönsted-Lowry acid?

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?

• Not a duplicate of this question which is the one about which I seek clarification. – Ray Bradbury Jan 4 at 15:49
• Why the downvote? – Ray Bradbury Jan 4 at 15:52
• " sodium ion is a conjugate acid of sodium hydroxide" - it is not. Protonate NaOH molecule and you'll find it. – Mithoron Jan 4 at 18:44
• @Mithoron I think I get it. As I understand it, and as someone else wrote on this SE, writing NaOH (aq) is really writing Na+ (aq) + OH- (aq). Protonating OH- gives H20, which is the conjugate acid, not Na+. In sum, is sodium ion not a Brönsted-Lowry acid? – Ray Bradbury Jan 5 at 15:05
• It is an aqua complex and has been so for quite a while now. – Jan Jan 19 at 8:59