DIVISION C

Part A. Reducing Sugars Answers

Materials

Benedict's Solution

Sample A = Regular non-cola soft drink

Sample B = Diet non-cola soft drink

Sample C = Clear Koolaid-type drink

Procedure

1. Obtain one tube containing 2 mL of Sample A, one tube of Sample B, and one tube of Sample C.

2. Using a 10 mL pipet, add 2 mL of Benedict's solution to each tube.

3. Heat each tube in a hot water bath for 2-3 minutes.

Note: Carefully carry your tubes to the lab assistant at the fume hood to heat them.

4. Retrieve samples.

5. Return to your lab bench and record your observations on the back side of this sheet.

Part B.  Sugar Hydrolysis

Materials

Benedict's Solution

Sample D = Regular non-cola soft drink, acid-treated*

Sample E = Diet non-cola soft drink, acid-treated*

Sample F = Clear Koolaid-type drink, acid-treated*

*Samples D, E, and F have been treated with dilute hydrochloric acid, boiled, cooled and neutralized with dilute carbonate base in advance.

Procedure

1. Obtain one tube containing 2 mL of Sample D, one tube of Sample E, and one tube of Sample F.

2. Using a 10 mL pipet, add 2 mL of Benedict's solution to each tube.

3. Heat each tube in the hot water bath for 2-3 minutes. Then, retrieve your samples.

4. Return to your lab bench and record your observations on the back of this sheet.

5. Answer the questions on the back of this sheet.

Record of Observations

Part A. Reducing Sugars

Sample A. _________________________________________________________________________

Sample B. _________________________________________________________________________

Sample C. _________________________________________________________________________

Part B.  Sugar Hydrolysis

Sample D. _________________________________________________________________________

Sample E. _________________________________________________________________________

Sample F. _________________________________________________________________________

Questions & Answers

1. In part A, which sample(s) contained a reducing sugar? (5 points) ______________________

2. In part B, which sample(s) contained a reducing sugar? (10 points) ______________________

3. Prior to acid hydrolysis, which drink(s) contained a reducing sugar? (5 points)

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4. Name the sugar(s) likely to be present in the drink(s) you listed for Q3? (5 points)

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5. After acid hydrolysis, which drink(s) contained a reducing sugar? (5 points)

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6. Name the sugar(s) likely to be present in the drink(s) you listed for Q5. (5 points)

_______________________________________________________________________________

7. Did any drink fail to give a positive reaction? If so, name it and explain why it did not and what sweetener may have been used. (5 points)

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