- Impure substance
Explanation:
A pure substance has only one kind of atom or molecule and has a definite composition throughout.
A refined substance is a substance without any impurity.
But a mixture is neither pure nor a refined substance.
A mixture consists of different elements or compounds combined physically in an unknown ratio.
The constituents of a mixture are not combined chemically, and so the mixture still shows all the properties of its constituents.
A mixture doesn't have a definite boiling or freezing point.
All of these properties of a mixture make it an impure substance.