Question

Fermentation of a Carbohydrate: Ethanol from Sucrose

1. What is the product obtained through anaerobic fermentation of a carbohydrate?

2. When air enters the fermentation mixture, aerobic oxidation takes place. What is the end product?

3. Amaretto liqueur is about 28% alcohol. What is its proof?

4. Why can't you get 100% ethanol by distillation of the solution from the fermentation process?

5. Why doesn't the fermentation process produce a concentration of ethanol greater than 10-15%?

6. Give a complete, balanced equation for the conversion of glucose (C6H12O6) into ethanol.

Carbohydrates

1.What functional group is present in glucose? Is glucose a reducing or nonreducing carbohydrate?

2. Draw and circle and label the hemiacetal functional group and the acetal functional group in each of the following carbohydrates:

a. sucrose

b.lactose

3. Which carbohydrate in question 2 would reduce Fehling's solution?

4. Name the functional group that links two monosaccharides in a disaccharide. Would that be the same kind of functional group linking monosaccharides in long-chain polysaccharides like amylose?

Answer 1

1) Ethanol, lactic acid and carbon dioxide.

2) Carbond dioxide

3) proof = % alcohol*2 = 28*2 = 56

4) Because azeotrope can be created by water and alcohol mixture.

5) Ethanol B.P is lesser than the water hence in distillation it evopartes easily So it comes above 10-15%.

6) C₆H₁₂O₆ → 2 C₂H₅OH + 2 CO₂

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1) Glucose is having -CHO functional group and it is a reducing sugar.

2)

3) lactose

4) Hemi acetal is formed because of -CHO and -OH groups. It is only the functional group for polysaccharides.

4)