Question

For "invert sugar", the correct statement(s) is/are
(Given : Specific rotations of $(+)$-sucrose, (+)-maltose, $L-(–)$-glucose and L-$(+)$-fructose in aqueous solution are $+{66}^{\circ },+{140}^{\circ },–{52}^{\circ }$ and $+{92}^{\circ }$, respectively)

• A. "Invert sugar" is an equimolar mixture of D-(+)-glucose and D-(–)-fructose
• B. On reaction with $B{r}_2$ water, "invert sugar" forms saccharic acid as one of the products
• C. "Invert sugar" is prepared by acid catalyzed hydrolysis of maltose
• D. Specific rotation of "invert sugar" is –${20}^{\circ }$

Answer 1

Answer: (A), (D)

Specific rotation of "invert sugar" is –${20}^{\circ }$

Invert sugar is an equimolar mixture of D-(+) glucose and D-(–) glucose.
$\to$ Specific rotation of invert sugar = $\frac{-92{}^{\circ }+52{}^{\circ }}{2}=-20{}^{\circ }$

$\to$ D-glucose on oxidation with $B{r}_2$-water produces gluconic acid and not saccharic acid.