Question

An organic compound $\left({\mathrm{C}}_8{\mathrm{H}}_{10}{\mathrm{O}}_2\right)$ rotates plane-polarized light. It produces pink colour with a neutral ${\mathrm{FeCl}}_3$solution. What is the total number of all the possible isomers for this compound?

Answer 1

1. It is given that the compound $\left({\mathrm{C}}_8{\mathrm{H}}_{10}{\mathrm{O}}_2\right)$ rotates plane-polarized light which means it is optically active.
2. Also, it is given that the compound gives pink colour on reaction with neutral ${\mathrm{FeCl}}_3$solution, this means that it is a phenol derivative (bear hydroxyl $\mathrm{OH}$ group).
3. So from the above two conditions, we can conclude that the compound can show three isomers, but because it is optically active each isomer will have two forms i.e $\mathrm{d}$ and $\mathrm{l}$.
4. So, ${\mathrm{C}}_8{\mathrm{H}}_{10}{\mathrm{O}}_2$ will have six isomers whose structures are shown here: