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Carbohydrates: classification, glucose structure, reactions
JEE Main level
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Difficulty 2 of 3
bm016
D-Fructose is a ketose, yet it reduces Tollens reagent. The reason is that
A
fructose has a free aldehyde group at C-1
B
the CH2OH group at C-6 is oxidised directly to CHO
C
in the basic medium fructose isomerises through an enediol to aldoses (glucose and mannose), which are then oxidised
D
Tollens reagent is acidic and oxidises ketones
Answer: C
In alkaline Tollens reagent the alpha-hydroxy ketone tautomerises through an enediol to an aldose. The aldose then reduces Ag+ to silver.
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