JEE Main levelOne or more correct optionsDifficulty 2 of 3bm020
Which of the following observations about glucose support the presence of a carbonyl (aldehyde) group in its open-chain form?
AReaction with acetic anhydride to give a pentaacetate
BFormation of an oxime with hydroxylamine
CFormation of n-hexane on heating with HI
DFormation of gluconic acid with bromine water
Answer: B, D
An oxime is a typical addition-condensation product of C=O, and bromine water oxidises CHO to COOH. Acetylation shows OH groups and the HI reduction to n-hexane shows an unbranched six-carbon chain; neither shows the carbonyl group.