. Which of the following materials fall in the category
of a pure substance?
(d) Hydrochloric acid
(e) Calcium oxide
To begin with, a pure substance is composed of one type of molecules only while mixtures
are composed of several constituents mixed in certain definite or indefinite proportions.
Amongst the following , pure substances are :
d) HCl(hydrochloric acid)
e) Calcium oxide (CaO, quick lime)
f) Mercury (Hg)
While the rest of the substances are all mixtures.
Milk is a colloidal solution, while brick, air and wood are all made up of multiple constituent molecules.
Hence, amongst the following options a, c, d, e and f fall under the category of pure substances.