Question

The change in optical rotation, with time, of freshly prepared solution of sugar is known as

• A. Rotatory motion
• B. Inversion
• C. Specific rotation
• D. Mutarotation

Answer 1

Answer: (D)

Mutarotation

Answer 2

$\alpha - \mathrm { D } -$ Glucose $[ \alpha ] = + 112 ^ { \circ }$ $( 36 \% )$ $\rightleftharpoons$ $\rightleftharpoons$ $\beta - D -$ Glucose $[ \alpha ] _ { D } = + 19 ^ { o }$ $( 64 \% )$

Glucose has two forms α and β. When either of these two is dissolved in water and allowed to stand, it gets converted to an equilibrium mixture of α and β forms.