Glucose forms an osazone with phenylhydrazine: C₆H₁₂O₆ + 3C₆H₈N₂ → C₁₈H₂₂N₄O₄ + C₆H₇N + NH₃ + 2H₂O…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Glucose forms an osazone with phenylhydrazine: . Use molar masses of for glucose, for phenylhydrazine and for the osazone. A sample of of glucose reacts completely. Find the mass of phenylhydrazine needed and the mass of osazone formed. Then find the amount of osazone from of fructose.
Need a reminder? The key ideaShow
The anomeric carbon is C-1 of an aldose. A group on the right of the Fischer projection points down in the Haworth ring and a group on the left points up. In a D sugar, the anomeric of the α form points down and that of the β form points up. The specific rotation is , with in dm and in g/mL.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Plan. Use the mole ratio of the equation.
Step 1. Moles of glucose. .
Step 2. Phenylhydrazine. . The mass is .
Step 3. Osazone from glucose. One mole of sugar gives one mole of osazone. The mass is .
Step 4. Fructose. The same mass of fructose is the same amount, of sugar, and it gives the same osazone. So of osazone forms.
Answer: of phenylhydrazine, of osazone, and of osazone from fructose.
Check. Only C-1 and C-2 take part, and fructose has the same groups as glucose on the other carbons.
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