Question

Which is a meso compound?
A.$\left( {2R,3R} \right) - 2,3 -$Dibromobutane
B.$\left( {2R,3S} \right) - 2,3 -$Dibromopentane
C.$\left( {2R,4R} \right) - 2,4 -$Dibromopentane
D.$\left( {2R,4S} \right) - 2,4 -$Dibromopentane

Answer 1

Meso compounds are the achiral chemical compounds which consist of two stereogenic centers. Stereogenic centers are also termed as chiral centers.

Complete step by step answer:
Meso compounds are the achiral chemical compounds which consist of two stereogenic centers. Stereogenic centers are also termed as chiral centers. Plane of symmetry results in the achiral nature of meso compounds. Meso compounds are generally superimposable on their mirror images. Meso compounds do not change or alter the direction of the plane polarized light. Therefore, meso compounds are considered as optically inactive compounds. The important example of meso compounds is tartaric acid. Meso compounds are light insensitive compounds.
The characteristics of meso compounds are as follows:
$1$. Meso compounds consist of more than two stereogenic centers.
$2$. Meso compounds are generally optically inactive.
$3$. These are achiral compounds having numbers of chiral centres.
$4$. Meso compounds have a plane of symmetry which results in the achiral nature of meso compounds.
$5$. Meso compounds are generally superimposable on their mirror images.
$6$. Meso compounds are light insensitive compounds.
From the above characteristics we can conclude that $\left( {2R,3R} \right) - 2,3 -$Dibromobutane is a meso compound because it consists of two stereogenic centers and has a plane of symmetry.
Therefore, $\left( {2R,3R} \right) - 2,3 -$Dibromobutane is a meso compound.
Hence, option $A$ is the correct option.

Note:
Always remember that the meso compounds are the achiral chemical compounds which consist of two stereogenic centers. Plane of symmetry results in the achiral nature of meso compounds. Meso compounds are light insensitive compounds.