Question

we cannot have isomers of first three member of alkane series. why?

Answer 1

Because they contain only 1,2,3 carbon atoms. And with 1,2,3 carbon atoms, it is not possible to have different arrangements of carbon atoms methane, ethane or propane.

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Answer 2

we cant have isomers of the first three members of the alkane series because of the following laws of isomers:-

1. the parent chain should have the most number of carbon atoms.

2. the branching cannot be done from the first or the last atom carbon atom of the structure.

now because of these laws we can see that with methane it is certainly not possible, with ethane it is not possible either as the branching is happening from only one carbon atom and violates both the laws,now propane cannot do the same as the branching is either going to happen from the first or the last carbon atom of the parent chain.

Thus we can say that the first three members of the alkane series cannot have isomers.

Parent chain means the basic chain on which the branching is to take place.

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