(Of course, it is not this simple.)
Acid-Base neutralization reactions
First we must recognize what an acid is, and what a base is then we must determine how they react with each other.
For now we will consider two definitions for the terms acid and base. (A third is also commonly used but will not discuss it until later;i.e. next semester.)
Arrhenius acids and bases&emdash;the first (historically) and simplest definition.
An acid is a substance which donates (releases) protons (H+).
A base is a substance which donates (releases) hydroxide (OH-).Thus HCl is an acid because in water it ionizes to form H+. NaOH is a base because it dissociates in water to form OH-.
However, there are substances that are basic, but do not contain a hydroxide. For example ammonia is a base. Another definition was created to deal with the observation that not all bases contain an OH-.
Brønsted-Lowry acids and bases.
An acid is a substance which donates (releases) protons (H+). Same as Arrhenius.
A base is a substance which accepts protons (H+).
When ammonia is added to water is accepts a protons from a water molecule.
(Of course, it is not this simple.)
Hydroxide (OH-) is a Brønsted base because it accepts H+ to make water.
This is important. A new definition must expand on
an older
definition. All bases that are Arrhenius bases must still be
considered bases under the new definition, and they
are.
Acids and bases react to form water and a salt. Acid base reactions are often referred to as neutralization reactions.
Of course, the reaction could be written differently...
as a complete ionic equation,
or...
as a net ionic equation.
When Brønsted bases react with acids water is not formed.
