Formation of Salts

Salts are ionic compounds made of a cation other than H⁺ ion and an anion other than OH^– ion. Salts are formed in many reactions involving acids and bases.

1. By Neutralization of Acids and Bases

Salts are the product (besides water) of a neutralization reaction. For example,

NaOH + HCl → NaCl + H₂O

KOH + HNO₃ → KNO₃ + H₂O

In general,

MOH + HX → MX + H₂O

The positively charged cation of the salt comes from the base. Therefore, it is called the basic radical. The negatively charged anion of the salt comes from the acid. It is therefore, called the acid radical of the salt.

For example, in the salt NaCl, the cation Na⁺ comes from the base NaOH and is its basic radical and the anion Cl^– comes from the acid HCl and is its acid radical.

2. By Action of Acids on Metals

In a reaction between an acid and a metal, salt is produced along with hydrogen.

Zn + H₂SO₄ → ZnSO₄ + H₂

3. By Action of Acids on Metal Carbonates and Hydrogen Carbonates

Salts are produced in reactions between acids and metal carbonates and hydrogen carbonates (bicarbonates) along with water and carbon dioxide.

CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

NaHCO₃ + HCl → NaCl + H₂O + CO₂

Type of salt and the nature of its aqueous solution