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Chemistry · 2025 · 2 marks
CBSE 2025 · Region 6 · Set 1 · Q21
How do you explain the following? (a) Presence of an aldehydic group in glucose. (b) Presence of five - OH groups in glucose.
How do you explain the following?
(a)
Presence of an aldehydic group in glucose.
(b)
Presence of five - OH groups in glucose.
Marking-scheme solution
(a)
Glucose gets oxidised to six carbon carboxylic acid (gluconic acid) on reaction with a mild
oxidising agent like bromine water. This indicates the presence as an aldehydic group /
(b)
Acetylation of glucose with acetic anhydride gives glucose pentaacetate which confirms
the presence of five –OH groups /
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CBSE Class 12 Chemistry past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.