What kinds of ions do acids and bases form in water?

Acids
produce hydrogen ions, H+, in water. Bases produce hydroxide ions, OH-.

A hydrogen ion is a bare proton that associates with a water molecule so the H+ ions
produced by an acid exist as H3O+ ions:

`H^+ + H_2O -> H_3O^+`

There are three accepted theories defining acids and bases:

1. The
Arrhenius theory defines an acid as substance that dissociates to produce H+ ions in solution
and a base as a substance that dissociates to produce OH- ions in solution, as per the answer to
your question.

2. The Bronsted-Lowery theory defines an acid as a proton
donor and a base as a proton acceptor. (Remember that a proton is the same as an H+
ion.)

3. The Lewis theory defines an acid as an electron pair acceptor and a
base as an electron pair donor.

Here are a few examples of these
definitions:

HCl is both an Arrhenius acid and a Bronsted-Lowry acid. It
dissociates to produce hydrogen ions in aqueous solution, and it donates a proton to a base.
These are two different ways of describing the same behavior.

Bases that
contain the hydroxide ion OH- are both Arrhenius and Br¸nsted-Lowry bases because they
dissociate to produce OH- ions that "accept" or bond to protons:

`H^+ + OH^(-) -> H_2O`

H+ is a Lewis acid because it will
"accept" or share a non-bonding pair of electrons on another atom or ion. For example,
it accepts an electron pair from the Lewis base F-:

`H^+ + F^(-) ->
HF`

Ammonia, NH3, is an example of all three types:

`NH_3
+ H_2O --gt NH_4^+ + OH^-`

Ammonia produces OH- by reacting with water. It
can also be said that it accepts a proton from water and that it donates an electron pair to an
H+ ion.