The phenomenon of the existence of an element in two or more forms having the same chemical properties but different physical properties. The different forms are called allotropic forms or allotropes.

What is denatured alcohol?

To prevent the misuse of industrial alcohol for drinking purpose, the ethanol meant for industrial purpose is denatured by adding small amounts of poisonous substance like copper sulphate or methanol or pyridine. This addition makes this ethanol unfit for drinking. This alcohol is called as denatured alcohol.

Isomers are the organic compounds having same molecular formula, but different arrangements of carbon atoms or simply different structures. For example, butane can exist in two isomeric forms such as n-butane and iso-butane.