Question

name the three alkane which do not show isomerism

Answer 1

the three alkanes are :
methane
propane
butane
as isomerism is shown by the compounds having more than 4 carbons in them.

Answer 2

$<b><i >$
Answer :- The three alkanes which don't show isomerism are Methane, Ethane and Propane.
These three alkanes have 1,2 and 3 carbon atoms respectively.

$\underline\bold{Reason:}$ For the alkanes which have 1, 2 or 3 carbon atoms it is not possible to get different chain structures and position isomers.As it is difficult get different strutures for molecules which contains 3 or less than 3 -Carbon atoms.