A solid mixture contains four consituents P, Q, and S.P consists of tiny graing and it is mixed with cement for plastering the walls. Q is a white solid which is recovered on a large scale from sea water by the process of evaporation. R is in the from of tiny particles of a material whose corrosion is called resting. And S is a white solid which is used in mking ordinary dry cells.
(a) What could P, Q R and S be ?
(b) How would you separte a mixture containing P, Q, R and S ?