Question

Why are there no isomers of propane?

Answer 1

Hint :The different arrangement of the atoms of a molecule in space is termed as isomers. The term isomer is inspired from the Greek language in which it means as iso as same ane mers as parts. The credit for the discovery and the development of isomerism goes to J. Von Liebig of Germany in $ 1823 $ .

Complete Step By Step Answer:
Isomers are classified into structural isomers and stereoisomers.
Structural isomers are further classified into ionisation isomerism, solvent or hydrate isomerism, linkage isomerism, coordination isomerism, coordination position isomerism, and polymerisation isomerism.
Stereo isomers are further classified into geometrical isomers which are further classified into cis, trans, facial and meridonial isomers, and the optical isomers.
The optical isomers are of three types as (i) $ [M\,{(AA)_3}\,] $ type with example as $ {[Co{(en)_3}]^{3 + }} $ . (ii) $ [M\,{(AA)_2}{B_2}\,] $ or $ [M\,{(AA)_2}BC\,] $ type with example as $ [CoC{l_2}{(en)_2}] $ . and (iii) $ [M\,(AA){B_2}{C_2}\,] $ type with example as $ [Co(en){(N{H_3})_2}C{l_2}] $ .
The structure of propane is as follows $ C{H_3} - C{H_2} - C{H_3} $ .As we can see the propane do not have enough atoms (mostly carbons to be considered) to arrange in different ways, thus propane do not have any isomer. But have a cyclic structure and a linear one.

Note :
For isomers to exist, there should be a minimum of four carbons for branching to take place. However iff there is hetero atom or any atom other than carbon and hydrogen then there could be an isomer of the propane. However as far as propane is considered, the atoms are not enough. But one linear and one cyclic structure only exists in the form of cyclopropane and propane only.