Explain Activity 1.2 NCERT Science Class 9

Activity 1.2 Explanation NCERT Science Class 9 Matter In Our Surroundings

Brief procedure:

Activity 1.2 asks us to dilute potassium permanganate solution.


When we add potassium permanganate in water, the colour of water changes to pink. DIlution decreases the colour intensity of the solution.

Activity 1.2 Explanation NCERT Science Class 9
Potassium permanganate in water.

A visible particle may consist of smaller invisible particles like molecules and atoms.

A small amount of Potassium permanganate contain millions of its molecules.

When we dissolve potassium permanganate in water, its molecule spread uniformly in the solution and give a pink appearance.

Dilution lowers the amount of the particles in subsequent solution. As a result, we see a lower colour intensity.

Dilution of a substance



A visible particle may have a large number of smaller particles in it.

Related facts:

Potassium permanganate is a disinfectant and finds its use in many skin infection and purification of water.

Potassium permanganate reacts with chemicals in onion and removes the foul odour. It also increases the shelf-life of onion pieces, so restaurants put onion in potassium permanganate solution.

Next: Experiment to show particles in a medium are continuously in motion: Activity 1.3.

See also:

Why there is no Change in volume of water when we add salt: Activity 1.1.

Activity list Chapter 1 Matter In Our Surroundings.

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