Question

Water is formed from the reaction of an acid and a base. Why is it not classified as a salt?

Answer 1

Because a salt is formally the compound formed from the metal and non-metal counterions, when an acid and a base are neutralized to give water.

Explanation:

Now normally we represent a neutralization reaction as a net ionic equation, viz.:

`H_3O^+ + HO^(-) rarr H_2O(l)`

Now, of course, these ionic species are not discrete entities; they are each accompanied by a counterion. The base is normally associated with a metal cation, and the acid by a non-metal anion.

For example:

`"Sodium hydroxide" + "Hydrogen chloride" rarr "sodium chloride "+"water"`

Or, symbolically,

`NaOH(aq) + HCl(aq) rarr NaCl(aq) + H_2O(l)`

Most of the time, the counterions, natrium and chloride, are just along for the ride; they are present in solution as `Na^+(aq)`, the aquated complex.

If I've missed the point of your question, I apologize.