Question

Which of the following molecules is expected to rotate the
plane of plane-polarised light?

Answer 1

Let us discuss it

Explanation:

Optical activity

They are those molecules that can rotate the plane of polarized light .

Condition necessary to show optical activity

They should have asymmetric carbon .

The mirror images should not be super-imposed.

"The two mirror forms that are not super imposed are called as optical isomers" .

The optical isomers are either :

D isomers (they rotate the plane of polarized light towards right )

L isomers (they rotate the plane of polarized light towards left )

For example :

The molecule CH₃-CH(Cl)(Br)-C₂H₅

                          1        2             3

In this 2nd carbon is asymmetric carbon (different groups attached ).