Question

Which of the following is/are correct?

• A. Oxidation of D-galactose by $HN{O}_3$ gives a meso product
• B. Aldose reacts with Fehling's solution, but not with $NaHS{O}_3$
• C. The smallest aldose to form a cyclic hemi-acetal must have 4 carbon atoms
• D. D-fructose and D-glucose can be differentiated using bromine water

Answer 1

Answer: (A), (B), (D)

The correct options are
A Oxidation of D-galactose by $HN{O}_3$ gives a meso product
B Aldose reacts with Fehling's solution, but not with $NaHS{O}_3$
D D-fructose and D-glucose can be differentiated using bromine water

Aldose has a cyclic structure which cannot react with $NaHS{O}_3$.
$B{r}_2/H_{2}O$ being a mild oxidising agent can only oxidise aldose to carboxylic acids but cannot oxidise ketoses.