Question

Can someone explain the Bronsted-Lowry definition of acids and bases?

I get that the acid donates an H ion and the base excepts. However, it says, "To recognize a Bronsted-Lowry acid, look for the H at the beginning of the formula. Then it says, "To recognize a Bronsted-Lowry base, first make sure it is not an acid. Then, look for the N in the formula.

Where does the N come in? I thought it was just the acid donating an H and a base accepting the H?

Answer 1

`"Acid + base " rightleftharpoons" Conjugate acid + conjugate base"`

Explanation:

Bronsted and Lowry characterized acid base behaviour on the basis of proton transfer, `H^+`. The acid was the proton donor, and the base the proton acceptor. I think your question refers to ammonia, i.e. `NH_3`, which is certainly a PROTON acceptor in aqueous solution, i.e.,

`NH_3(aq) + H^(+) rarr NH_4^+ + HO^-`

Capisce? So, in relation to your question, nitrogen containing species are often basic, and contain a neutral nitrogen ATOM, conceived to have a lone pair, available for donation to `H^+`.

Lewis proposed an alternative acid-base theory, in which the the base was the elecron pair donor, and the acid the electron pair acceptor, which allows a much broader church of acid-base behaviour. `H^+`, whatever this is, and IS very much a conceptual species, is a potent electron pair acceptor, i.e.

`H^+ + ""^(-)OH rarr H_2O`