A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water.
The neutralization of a strong acid and strong base has a pH equal to 7. The neutralization of a strong acid and weak base will have a pH of less than 7, and conversely, the resulting pH when a strong base neutralizes a weak acid will be greater than 7.
Consider the reaction between HCl and NaOH in water:
A weak acid, weak base reaction can be shown by the net ionic equation example:
H+(aq)+NH3(aq) ⇋ NH+4(aq)