Question

How many stereoisomers are possible for 2-methyl-1,3-dichlorohexane?

Answer 1

There are four possible stereoisomers for 2-methyl-1,3-dichlorohexane.

Explanation:

The structure of 2-methyl-1,3-dichlorohexane is

`"ClCH"_2 stackrelcolor(blue)("*")("C")"H"("CH"_3)stackrelcolor(blue)("*")("C")"HClCH"_2"CH"_2"CH"_3`.

We see that there are two chiral carbons (marked with an asterisk) — they are attached to four different groups.

The maximum number of stereoisomers is `2^n`, where `n` is the number of chiral centres.

There is no internal plane of symmetry, so the number of stereoisomers is `2^2 = 4`.

Their structures are