Question

33.A, B and C are all liquids. Liquid A has a comparatively low boiling point. On heating, liquid A vaporises

completely without leaving behind any residue. Liquid A is being used increasingly as a fuel in motor vehicles either alone or by mixing with petrol. Liquid B has a very high boiling point. It also vaporises completely on heating, without leaving any residue. Liquid B is a conductor of electricity and used in making thermometers. Liquid C has a moderate boiling point. On heating, liquid C vaporises leaving behind a white solid D which is used in cooking vegetables. The condensation of vapours from C give a liquid E which turns anhydrous CuSO4 to blue. (a) Which liquid could be an element ? Name this element. (b) Which liquid could be a mixture ? Name this mixture. (c) Which liquid could be a compound ? Name this compound. (d) What could the solid D be ? (e) What do you think is liquid E ?​

Answer 1

(a) Which liquid could be an element? Name this element.

Answer- Liquid B is Mercury. Mercury is used in making thermometers. Mercury is also a metal and it is a conductor of electricity.

(b) Which liquid could be a mixture? Name this mixture.

Answer- Liquid C is a salt solution. The salt solution, when boiled, leaves salt as a residue. Salt is used in cooking.

(c) Which liquid could be a compound? Name this compound.

Answer- Liquid A is alcohol. Alcohol, when boiled does not leave any residue. It is also used in motor vehicles nowadays.

(d) What could solid D be?

Answer- Solid D is sodium chloride. It is also known as common salt. It is also added in food.

(e) What do you think is liquid E?

Answer- Liquid E is water. When we heat liquid C(salt solution), it leaves water vapours. When we condense water vapour, we get pure water. When we add water to anhydrous CuSO4, the powder turns from white to blue.​