D(+) Glucose reacts with hydroxylamine and forms oxime. The structure of oxime would be:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → D-glucose oxime
Hydroxylamine reacts only with the aldehyde group (C-1) of the open-chain form of glucose; the four chiral carbons C-2 to C-5 are not touched, so the oxime keeps the configuration of D-glucose:
\( \ce{CHO-(CHOH)4-CH2OH + NH2OH -> CH(=N-OH)-(CHOH)4-CH2OH + H2O} \)
In the Fischer projection of D-glucose the –OH groups are on the right, left, right, right at C-2, C-3, C-4 and C-5. Only structure (4) has this pattern below CH=N–OH.
Why the other options are incorrect
Option (1) — Incorrect. –OH is on the left at C-4 (right, left, left, right); this is the oxime of D-galactose, the C-4 epimer of glucose.
Option (2) — Incorrect. –OH is on the left at C-2 (left, left, right, right); this is the oxime of D-mannose, the C-2 epimer of glucose.
Option (3) — Incorrect. –OH groups are left, right, left, right; C-2, C-3 and C-4 are all inverted, which is the oxime of D-idose, not of glucose.
NCERT (2026-27 edition):
Structure of Glucose – …
