Question
An organic compound with the formula C _ 6 H _ 12 O _ 6 forms a yellow crystalline solid with phenylhydrazine and gives a mixture of sorbitol and mannitol when reduced with sodium. Which among the following could be the compound?
BITSAT
Chemistry
Biomolecules
2020
BITSAT 2020
BITSAT Chemistry Question (2020) — Solution
Options
- A. fructose
- B. glucose
- C. mannose
- D. sucrose
Answer
A. fructose
Step-by-step solution
Since the compound forms a yellow crystalline solid, i.e. osazone with phenylhydrazine, it may be an aldohexose or a ketohexose. Further, since on reduction, compound forms a mixture of sorbitol and mannitol, it must be a ketohexose, i.e. fructose. Recall that glucose on reduction gives only one alcohol glucitol (Sorbitol)
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