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Question
Give two evidences for presence of formyl group in glucose.
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Solution
- Glucose gets oxidized to a six-carbon monocarboxylic acid called gluconic acid on reaction with bromine water which is a mild oxidizing agent. Thus, the carbonyl group in glucose is in the form of formyl (–CHO).
- Hemiacetal group of glucopyranose structure is a potential aldehyde (formyl) group. It imparts reducing properties to glucose. Thus, glucose gives positive Tollen’s test or Fehling test.
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