(a) What are combustible substances ? Name three combustible substances.
(b) What are non-combustible substances ? Name three non-combustible substances.
(a) Why does common salt get wet during the rainy season ?
(b) How can this impurity be removed ?
(c) Name a substance which changes the blue colour of copper sulphate crystals to white.
(d) Name two crystalline substances which do not contain water of crystallisation.
Glass is a crystalline substance.