Acid-base reactions

For much of organic chemistry, an acid may be defined as a compound that can transfer a proton (H⁺) to a base, and a base may be defined as any entity with an unshared pair of electrons (and therefore capable of accepting a proton). In acid-base reactions a proton is transferred from an acid to a base.

If the acid and base are neutral molecules, the product is a positive ion and a negative ion and is known as a salt. A specific example is the reaction of benzoic acid with sodium hydroxide to form sodium benzoate (and water, which always forms as a by-product when the base is hydroxide ion). Sodium benzoate is often added to breads and baked goods in very small amounts to preserve freshness.