Question

hoe can we check wgether the given substance is pure or not

Answer 1

If the substance is made up of only one type of element it is a pure substance.
If the substance is made up of two or more elements it is a impure substance.

Hope this will helps you

Answer 2

To determine if a substance is pure in school laboratories, we can check the substance's melting or boiling points or use chromatography (see Separation Techniques). A pure solid has a constant/fixed melting point. ie. it will melt completely at one temperature only.