Acids, Bases and Neutral Substances: quick revision, 12 bites

Three Categories: Acid, Base, Neutral

Every substance is one of these three.

Substances around us can be grouped into **acids**, **bases**, or **neutral** substances based on their chemical nature.

Takeaway. Acids, bases and neutral substances differ in taste, feel and their effect on indicators.

What Are Indicators?

Indicators reveal a substance's true nature.

Takeaway. Indicators change colour or smell to tell us the nature of a substance.

Litmus: The Classic Test

One paper, two colours, three answers.

Takeaway. Litmus paper is the simplest way to identify acids, bases and neutral substances.

Never Taste Unknown Substances

Tasting chemicals in a lab is dangerous.

Takeaway. Use indicators, not your tongue, to identify acids and bases in the lab.

Acids and Bases Around You

Your kitchen is a chemistry lab.

Takeaway. Acids and bases are common in food, cleaning agents and medicines.

Turmeric: A Natural Indicator

Your kitchen spice is also an indicator.

Takeaway. Turmeric changes colour only in bases, making it a useful natural indicator.

Acids vs Bases: Side by Side

Sour vs bitter — know the difference.

Takeaway. Acids and bases differ in taste, feel, litmus reaction and everyday examples.

Litmus Comes From Lichen

Litmus is made from living organisms.

Litmus is a natural dye extracted from **lichen**, a plant-like organism. It is the most commonly used natural indicator in school laboratories.

Takeaway. Litmus, the classic indicator, is a natural dye obtained from lichen.

Olfactory Indicators: Smell the Change

Some indicators work through your nose.

Olfactory indicators change their **smell** in acids and bases instead of their colour.

Takeaway. Olfactory indicators detect acids and bases by a change in smell.

Remember the Litmus Rule

One line saves you marks.

Takeaway. Memorise the litmus colour rule — it is the most frequently asked point in exams.

B-R-B: Blue to Red for Base? No!

A quick trick to never mix it up.

Think **"A-B-R"**: **A**cid → **B**lue litmus → **R**ed. And **"B-R-B"**: **B**ase → **R**ed litmus → **B**lue.

Takeaway. Use the A-B-R and B-R-B pattern to recall litmus colour changes instantly.

Ant Stings and Baking Soda

A base soothes an acid sting.

An ant sting injects **formic acid**, causing pain. Rubbing baking soda (a base) on the skin neutralises the acid and gives relief.

Takeaway. Bases like baking soda neutralise acid stings and reduce pain.