Question

why milk regarded as a mixture and not as a pure substance

Answer 1

Actually milk is an impuresubstance because it is made up of several elements and minerals like water , carbohydrates,etc. But if not seen logically it is purebecause we do not mix the minerals in it. ... A pure substanceis one that is composed of only one type of atom or one type of molecule.

Answer 2

Milk is regarded as a mixture and not as a pure substance because milkConsists of fatty acids, proteins, minerals, etc. Hence it is a colloidalmixture.