Question

Which of the following is/are optically active compounds?
A.n-butyl bromide
B.sec-butyl bromide
C.isobutyl iodide
D.tert-butyl chloride

Answer 1

Before solving this question, we should know about the chirality and optically active compounds. Chirality is the property of the material in which the mirror image of it is non-superimposable. Not every naturally occurring material shows Chirality.

Complete step by step solution: The compounds that can perform optical rotation are said to be optically active. All the chiral compounds are capable of optical rotation., Hence they are optically active.
Let us first understand what Chiral compounds are. Chiral compounds are compounds that are a mirror image of each other but are not superimposable and the pair of them are known as enantiomers.
They do not have the plane of symmetry, so we cannot divide them into two halves but they are optically active. Chirality and stereoisomers play a vital role in the field of chemistry as it tells us about the reason behind the formation of various organic structures.
So, A carbon atom that has four different groups attached to it will be considered a Chiral compound and will be able to perform optical rotation as well.
In n-butyl bromide, the atoms attached to the carbon atom are not different.. Therefore it is not optically active.
Sec-butyl bromide, the groups that are attached to the carbon atom are different, so it shows chirality and optical rotation., hence it is optically active.

In isobutyl iodide, two $-C{{H}_{3}}$ groups are present., Hence it is not optically active.
Tert-butyl chloride has three $-C{{H}_{3}}$ groups., so they are not chiral and Hence not optically active.

Note: Achiral is the opposite of chiral, They are the superimposable image of each other. They are identical and are not optically active. They have a center of symmetry and contain a stereocenter which is known as meso.