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Chemistry · 2026 · 2 marks
CBSE 2026 · Region 3 · Set 1 · Q21
How do you explain the following? (a) Presence of a straight chain in glucose (b) Presence of five - OH groups in glucose which are attached to…
How do you explain the following?
(a)
Presence of a straight chain in glucose
(b)
Presence of five - OH groups in glucose which are attached to different carbon atoms
Marking-scheme solution
(a)
Glucose on reaction with HI forms n-hexane which confirms the presence
of a straight chain (or chemical equation).
(b)
Glucose on reaction with acetic anhydride gives stable glucose
pentaacetate which confirms the presence of five -OH groups (or chemical
equation).
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CBSE Class 12 Chemistry past-paper question from the 2026 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.