Question

How many optical isomers does glucose have?

Answer 1

Glucose is simple sugar represented by the molecular formula ${{C}_{6}}{{H}_{12}}{{O}_{6}}$. It is kept in the category of carbohydrates and it is mainly made up of plants during photosynthesis from water and carbon dioxide by using energy from sunlight.

Complete step by step answer:
Molecules which have the same molecular formula but different arrangement of molecules are known as isomers. Isomers are of two types: Geometrical isomers and Optical isomers. Optical isomers are named as this because of their effect on plane polarized light. Simple substances which show optical isomerism exist as two isomers which are known by the name enantiomers. A solution of enantiomer which rotates the plane of polarization in a clockwise direction are known as (+) enantiomer while a solution of the other enantiomer which rotates the plane of polarization in an anti-clockwise direction are known as the (-) enantiomer.
Number of optical isomers can be calculated from the formula ${{2}^{n}}$ where n represents the number of chiral centers whereas chiral centers is an atom which has four different groups bonded to it in such a manner that it has non-superimposable mirror image.
Hence, the number of optical isomers in glucose is given by ${{2}^{n}}$ where n is 4, therefore ${{2}^{4}}$ i.e. 16 isomers.

Note: When optically active substances are made in the lab then they often occur as exactly half mixture of the two enantiomers which are known as a racemic mixture or racemate and it has no effect on plane polarized light.