The products of any acid-base neutralization reaction are a salt and water. A salt is formed from the positive ion of the base and the negative ion of the acid.
Acids are substances that produce hydronium ions when dissolved in water; bases form hydroxide ions when they meet water. Salts consist of any compound resulting from a neutralization reaction. Some salts form crystalline solids while others, called hydrates, contain water molecules.
Common table salt forms when a strong acid, hydrochloric acid, reacts with a strong base, sodium hydroxide. Water forms from the positive ion of the acid, which is the hydrogen ion and combines with the negative ion of the base, which is the hydroxide ion.