Choose the solutions from among the following mixtures:

Soil, Sea-water, Air, Coal, Soda-water

Give reason why:

(a) copper metal is used for making electric wires.

(b) graphite is used for making electrode in a dry cell

How would you confirm that a colourless liquid given to you is pure water?

Is air a mixture or a compound? Give three reasons for your answer.

Give two reasons for supposing that water is a compound and not a mixture.