Question

The above process in which $\alpha$ and $\beta$ form remain in equilibrium with acyclic form and a change in optical rotation is observed which is called as

${\left[ \alpha \right]_n} = + {112^0}$ ${\left[ \beta \right]_n} = + {19^0}$
(A) Mutarotation
(B) Epimerization
(C) Condensation
(D) Inversion

Answer 1

Carbohydrates are existing in cyclic structures, the cyclic structures of sugars which differ in the direction of the hydroxyl group attached to ${C_1}$ carbon are called anomers. These two anomers are of the same molecular formula and only differ at the configuration of ${C_1}$ , undergoing a change in the optical rotation.

Complete answer:
Given molecule is a class of carbohydrates. These are the chemical constituents with the general molecular formula of ${C_m}{\left( {{H_2}O} \right)_n}$ .
The atoms of hydrogen and the oxygen were in the ratio of $2:1$ .
Given compound is Glucose, with a molecular formula of ${C_6}{H_{12}}{O_6}$ .
The glucose can exist in two different forms. One is the $\alpha$ form and the other is the $\beta$ form.
These two forms are with the same molecular formula but differ in the direction of the hydroxyl group at ${C_1}$ carbon.
These two forms are in equilibrium with an acyclic glucose molecule.
These two forms rotate the plane polarised light in two directions and have a different specific rotation value.
The $\alpha$ form has an optical rotation of $+ {112^0}$ and the $\beta$ form has an optical rotation of $+ {19^0}$ .
The change in the optical rotation is due to the change in the equilibrium of the anomers, which can be termed as mutarotation.
Thus, option A is the correct one.

Note:
Epimerization is the difference in the attached direction of the hydroxyl group at any carbon in the cyclic structure of carbohydrates. Inversion can be understood as the process of conversion of glucose into fructose. We can understand condensation as the process of combining simple molecules into complex molecules.