NCERT Solutions Curiosity Chapter 6 .3.4 What is soluble in water; what is not? — In-text Questions

Book page 1126 Updated on2026-09-05

Q1.

Do liquids like oil, vinegar and honey dissolve in water? Explore.

Answer

Liquids behave in both ways too. Take three glasses of water and add a spoonful of each, stir, then leave them undisturbed for some time.

Liquid added to water	What you see	Conclusion
Vinegar (sirka)	Mixes completely; the water stays clear	Soluble — mixes fully with water
Honey	Sinks first, but on stirring it mixes completely and the water turns uniformly pale	Soluble
Mustard oil	Breaks into droplets while stirring, then collects as a separate layer on top when left alone	Insoluble

So some liquids get completely mixed with water; some do not mix and form a separate layer when left undisturbed for some time.

Did you know? Oil floats on top because it is lighter than the same volume of water. This is exactly what a cook does when she pours off the oil floating on a pickle, and what workers do when they skim spilt oil off a pond.

Q2.

What about the gases present in water?

Answer

Gases dissolve in water too — some well, some hardly at all.

Oxygen from the air dissolves in the water of ponds, rivers and the sea. It is very important for the survival of the animals and plants that live in water — fish take in this dissolved oxygen through their gills.
Carbon dioxide also dissolves in water. A cold drink is water with carbon dioxide forced into it — the fizz you hear on opening the bottle is that gas escaping.
Gases like nitrogen dissolve only in very small amounts.

How you can see dissolved gas: keep a glass of tap water on the table for an hour. Tiny bubbles appear on the inside walls — that is dissolved air coming out as the water warms up. Warm water can hold less dissolved gas than cold water.

Try This: Watch an aquarium. The air pump bubbles are not there for decoration — they keep dissolving fresh oxygen into the water so the fish can breathe.

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