475

37 Experiment 5. The discovery of acetone by transferring it to iodoform. Place 1 drop of iodine solution in potassium iodidein a test tube. Add 10% NaOH solution dropwise. The solution should become discolored. Add 1 drop of acetone to the discolored solution. Hold the tube in a fist. From the heat of the hands drops a yellowish-white sediment with a characteristic odor of iodoform. Can ethyl alcohol participate in the formation of iodoform?What compounds can be detected using iodoform test? CH 3 C CH 3 O + 3I 2 + 3NaOH C C CH 3 O + I I I 3NaI + 3H 2 O Stage of discoloration of iodine solution + + C C CH 3 O I I I NaOH CHI 3 CH 3 C ONa O Stage of formation of iodoform Experiment 6. The discovery of acetic acid. Place 3 drops of acetic acid and water in a test tube. To the solution, add 2–4 drops of 10% NaOH solution until the acid is completely neutralized. Use a litmus test to test the reaction of the solution. Then add 2–3 drops of 1% solution of FeCl 3. Appearance of yellow-red coloration of iron (III) acetate. Heat the solution to a boil. A red- brown precipitate of insoluble iron diacetate hydroxide forms. The solution over the precipitate becomes almost colorless. Write the equation for the formation of iron (III) acetate and its hydrolysis accompanied by the formation of iron (III) diacetate hydroxide. Experiment 7. Preparation of ethyl acetate. In a dry tube place the sodium acetate powder (about 1 g) and 3 drops of ethyl alcohol. Add 2 drops of concen- trated H2SO4 and gently heat on the spirit. After a few seconds, there is a smell of ethyl acetate. Write the equations for the formation of ethyl acetate. By what mechanism is it implemented? What is the role of H2SO4 in the esterification reaction?