Lecture
1. Three numbered test tubes contain solutions of the following substances:
V a r i a n t 1. Glycerol, glucose, formaldehyde.
V a r i a n t 2. Formaldehyde, glucose, ethanol.
V a r i a n t 3. Acetic acid, glycerol, glucose.
V a r i a n t 4. Ethanol, sucrose, glucose.
Using a single reagent (which one?), determine which test tube contains each of the substances.
2. Experimentally prove the presence of starch in white bread and potatoes.
3. Prove that the sucrose molecule contains glucose residues. To do this, carry out the hydrolysis of sucrose.
Hydrolysis of Sucrose
Place 0,3–0,5 g of sucrose and 7–8 cm3 of water into a test tube. Divide the solution into three parts. To the first test tube add 1 cm3 of dilute sulfuric acid, boiling chips, and boil for 1–2 minutes. To the second test tube also add acid, but do not heat it. The third test tube is the control. Then carry out the qualitative reaction for glucose in all the test tubes.
Additional Experiment
Experimentally prove the presence of glucose in fruits (apples, pears, grapes, etc.)
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