Question

Equimolar mixture of a $\alpha -D(+)$- glucose and $\beta -D(+)$-glucose has specific rotation (${\left[\alpha \right]}_D$) is:

• A. $-{92.4}^o$
• B. $+{112.5}^o$
• C. $+{52.5}^o$
• D. $-{19.2}^o$

Answer 1

Answer: (C)

$+{52.5}^o$

The specific rotation of α-D-glucopyranose decreases from +112° to +52.5°.

The specific rotation of β-D-glucopyranose increases from +19° to +52.5°.

The specific rotation of equimolar mixture of $\alpha$ - D(+) - glucose and $\beta$ - D(+) - glucose has a specific rotation ${52.5}^0$.

Hence, the correct option is C.