Question

How can you show that some solids like sugar, salt are soluble in water whereas solids like chalk powder and sand are not soluble in water?

Answer 1

Collect samples of sugar, salt, chalk powder and sand. Take four beakers. Fill each one of them about two-third with water. Add a teaspoonful of sugar to the first beaker, salt to the second, chalk powder to the third and sand to the fourth. Stir the contents of each beaker with a spoon/stirrer. Wait for a few minutes and observe what happens to the substances added to the water.
Note down your observations in the following table.
Table: Mixing different solid materials in water

S. No.	Substance	Disappears in water / does not disappear
1.	Sugar	Disappears completely in water
2.	Salt	Disappears completely in water
3.	Chalk powder	Does not disappear in water
4.	Sand	Does not disappear in water

Inference: (i) Sugar and salt are soluble in water.
(ii) Chalk powder and sand are insoluble in water.