What is a neutralisation reaction? - BBC Bitesize (2024)

• An acid and alkali will neutralise each other and produce a salt and water. This is called a neutralisation reaction.
• The name of the salt produced can be worked out from the names of the acid and the alkali.
• Chemical equations can be written to describe a neutralisation reaction.

Watch this video to find out more about reactions.

While you're watching, try to listen out for as many and as you can, and the names of the salts they produce.

Did you know?

Usually neutralisation is an reaction, so the reaction mixture warms up during the reaction.

have scientific names. For example, the scientific name of table salt is sodium chloride.

Names of salts can be worked out from the names of the acid and the alkali that react to make them.

There are two parts to a salt name:

1. The first word is a metal, taken from the alkali.
2. The second word ends in ~ide or ~ate, taken from the acid.

For example, table salt – or sodium chloride - is produced when hydrochloric acid reacts with the alkali sodium hydroxide. The word sodium is taken from the alkali, and the word chloride from the acid.

hydrochloric acid + sodium hydroxide → sodium chloride

Alkalis are typically metal hydroxides, such as the sodium hydroxide used to make table salt.

There are three acids that are commonly used. These are hydrochloric acid, nitric acid, and sulfuric acid.

These three acids use different words for the name of salts produced by them:

• A salt made from hydrochloric acid will end in chloride
• A salt made from nitric acid will end in nitrate
• A salt made from sulfuric acid will end in sulfate

Did you know?

Working backwards, the names of the acid and alkali reacting can be predicted from the name of the salt.

For example, the salt lithium nitrate would have been made from lithium hydroxide and nitric acid.

Word equations

Neutralisation reactions can be described using like a word equation. This uses the scientific names for the acid and alkali placed on the side of the equation. The scientific name for the salt goes on the side, together with water.

For example:

Nitric acid + sodium hydroxide → sodium nitrate + water

Acid + alkali → salt + water

Symbol equations

A symbol equation describes a reaction more precisely using chemical symbols and formulas. Here is an example of a word equation and a symbol equation describing the same reaction.

Nitric acid + sodium hydroxide → sodium nitrate + water

HNO₃ + NaOH → NaNO₃ + H₂O

Acids always have hydrogen (H) in them. For example, hydrochloric acid has the formula HCl, sulfuric acid is H₂SO₄ and nitric acid as shown in the example is HNO₃.

Alkalis usually have the hydroxide group OH in their formula, such as the sodium hydroxide (NaOH) in the example.

The symbol equation is helpful in seeing where the water came from.

The H from the acid combines with the OH from the alkali to make the water (H₂O). The other elements are used in making the formula of the salt.

On the lookout for more resources to get your students excited about chemistry? In this video from BBC Series Chemistry Bites, science presenter Jon Chase breaks down acids, alkhalis and indicators.

BBC Teach has thousands of free, curriculum-linked resources to help deliver lessons - all arranged by subject and age group.