8-32a - Organic Chemistry (Mcmurry)

Question

Which of the reactions below would result in a product mixture that would rotate plane-polarized light?

a) 

Step-by-Step Solution

Answer

The product of this reaction will not rotate plane polarized light.

Plane-polarized light

Light is an electromagnetic wave consisting of electric component as well as magnetic component. For getting plane polarized light, a Polaroid is used most commonly Nicol prism is used this Polaroid will convert three dimensional light into two dimension because it will allow only one component of light i.e. vertical component of light to pass through that. Therefore, we can say that a light that will oscillate only in a single plane in the direction of light of propagation is called plane polarized light.

                                Plane polarized light

Chiral Molecules

When in a molecule plane of symmetry is not presentand the molecule is also having four different atoms. The molecules which are mirror images of each other but are non- superimposable are known as chiral molecules. For example:

                           Chiral molecule

Observation

This reaction is a hydrogenation reaction and the reagent  is most commonly used in hydrogenation reaction. It is a reduction reaction. In hydrogenation reaction, hydrogen atoms will be added on the double bonds and we will get the product of the reaction as shown below:

                                        Hydrogenation reaction

In this molecule no chiral center is present therefore, the molecule is not chiral or we can say that the molecule is achiral and achiral molecule will not rotate plane polarized light. Hence, the product of this reaction will not rotate plane polarized light.