why hydrocarbons having less than 4 carbon atoms does not show isomerism
because methane , ethane and propane cant be arranged in the form of branched chain. They can be arranged only in the form of straight chain. Thus they dont show isomerism.
Atleast 4 carbon atoms are required for arranging in the form of branched chain. thus they show isomerism.
Atleast 4 carbon atoms are required for arranging in the form of branched chain. thus they show isomerism.