Question

explain substitution reaction

Answer 1

HEY!!

A substitution reaction is a chemical change in
which an  element (elements) of a compound replace the element(elements) from the molecules of another compound. 

Example:-

Iron (Fe) substitutes copper (Cu)

Answer 2

The reaction in which one or more Hydrogen atoms of a hydrocarbon are replaced by some other atoms like Chlorine is called a Substitution Reaction.

Saturated Hydrocarbons undergo Substitution reaction in presence of sunlight.

Hope it helped. Good luck.