Question

Meso compound do not show optical activity because:
A.They do not contain chiral carbon atoms
B.They have non- super imposable mirror images
C.They contain plane of symmetry
D.They do not contain plane of symmetry

Answer 1

Hint: Optical rotation, even known as polarisation rotation or circular birefringence, is the movement of the polarisation plane orientation around the linearly polarised optical axis of light as it passes through some material. Optical activity occurs only in chiral materials which lack the symmetry of a microscopic mirror.

Complete answer:
A meso compound or meso isomer is a non optically active member of a group of stereoisomers, of which there are at least two optically active. This means that the molecule is not chiral although it contains two or more stereo genic centres.
They are achiral compounds, which have several chiral centres. It is superimposed on its mirror image and, despite its stereo centres, is optically inactive.

It has an internal plane of symmetry which divides the compound in half. Via the inner mirror these two halves reflect one another. Stereocenter stereochemistry can "cancel out." What this means here is that if we have an internal plane that divides the compound into two symmetrical sides, the stereochemistry of both the left and the right should be opposite to each other. Thus, result in optically inactive. Cyclic compounds are also theoretically meso.
Meso compounds don't exhibit optical activity because of the presence of a plane of symmetry because of which optical activity cancels out.

Note:
An asymmetric carbon atom (chiral carbon) is a carbon atom attached to four different atom types or atom groupings. Le Belvan't Hoff rule states that the quantity of stereoisomers of a chemical compound is\[2n\], where n represents the quantity of asymmetric carbon atoms (unless, there's an inside plane of symmetry).