Naming Salts

The name of every salt consists of two parts. The first part comes from the metal, and the second part comes from the acid. To name a salt, it’s important to follow this simple structure:

  • Hydrochloric acid reactions always produce a chloride salt (for example, potassium chloride)
  • Nitric acid reactions always produce a nitrate salt (for example, sodium nitrate)
  • Sulfuric acid reactions always produce a sulfate salt (for example, copper sulfate)

For example, when copper carbonate reacts with sulfuric acid, it produces the salt copper sulfate along with carbon dioxide and water. The equation for the reaction is:

Copper carbonate + Sulfuric acid → Copper sulfate + Carbon dioxide + Water

Formulae of Salts

Salts have no overall charge because the sum of the charges on the ions that make up the salt is equal to zero. The table below shows some common ions and their charges.

Group 1 metalsM⁺ (e.g. Na⁺, K)
Group 2 metalsM²⁺ (e.g. Mg²⁺, Ca²⁺)
Group 7 halidesX⁻ (e.g. Cl⁻, Br⁻)
Copper (II)Cu²⁺
Iron (II)Fe²⁺
Iron (III)Fe³⁺

If we know the ions present in a salt, we can work out the formula by balancing the charges.

For example, let’s look at the salt formed by the neutralisation reaction between sodium hydroxide (NaOH) and hydrochloric acid (HCl). The products of this reaction are water and sodium chloride (NaCl).

NaOH + HCl NaCl + H2O

The sodium ion (Na⁺) has a charge of +1, while the chloride ion (Cl⁻) has a charge of -1. To balance the charges, we need one sodium ion and one chloride ion, which gives us the formula NaCl.


What is the formula of sodium carbonate?

The formula for sodium carbonate is Na2CO3.

Sodium carbonate consists of two types of ions:

• Na⁺ (sodium)

• CO3²⁻ (carbonate)

The sum of the charges of these ions must equal zero. This means that two Na⁺ ions are needed to balance the -2 charge from the CO3²⁻ ion. So, the two Na⁺ ions carry a total charge of +2, while the CO3²⁻ ion has a total charge of -2, resulting in a neutral compound.