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Neutralisation

Neutralisation is the reaction in which an acid and a base react to form salt and water, usually with release of heat.

In one line: Neutralisation means balance: acid and base cancel excess action.

Practice This Concept

Understand it

Neutralisation is one of the most useful ideas in this chapter because it appears in stomach medicine, soil treatment, and sting relief.
When an acid is too strong, a base can reduce its effect.
When a base is too strong, an acid can reduce that effect.
The final result is a safer, less extreme solution.

Example

An antacid tablet helps reduce excess acid in the stomach by neutralising it.

Rule to remember

Acid + base → salt + water.

In many cases, heat is also produced during the reaction.

Example: HCl + NaOH → NaCl + H₂O.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

1If an acidic soil is treated with slaked lime, the base in slaked lime reduces the excess acid in the soil.
2The soil becomes more suitable for plant growth after neutralisation.

Method you can reuse

1First identify which substance is acidic and which is basic.
2Then explain that they react to reduce excess acidity or basicity.
3Finally state the products salt and water, and mention any practical use.

Visual tip

A simple flow diagram can show an acidic stomach on one side, antacid in the middle, and a less acidic stomach on the other side.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

Why does an antacid tablet help when a person feels acidity in the stomach?

Think first, then show answer

It helps because the antacid neutralises the extra stomach acid, reducing irritation and making the stomach content less acidic.

Common wrong answer

A common wrong answer is to say the acid simply disappears.

Why it loses marks: It reacts with a base to form new substances.

Don't mix this up

Students sometimes write only salt is formed and forget water. They also forget that the reaction reduces excess acidity or basicity.

Exam tip

In exam answers, always mention the role of acid, base, and the useful result, especially in daily-life examples.

Write it in the exam

Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.

How CBSE asks it

Questions often ask for the reason antacids work, why acidic soil is treated with lime, or what products are formed in neutralisation.

1
Enough for 1 mark
Neutralisation is the reaction in which an acid and a base react to form salt and water, usually with release of heat.
2
Add for 2 marks
Example: An antacid tablet helps reduce excess acid in the stomach by neutralising it.
3
Add for 3 marks
Neutralisation is one of the most useful ideas in this chapter because it appears in stomach medicine, soil treatment, and sting relief.

MCQ Quiz

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