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AIM: The purpose of this experiment was to investigate the properties of the alcohols ethanol, 1-butanol, 2-butanol and 2-methyl-2-propanol, and to compare the reactivities of a series of isomeric alcohols (with the formula C4H9OH). EQUIPMENT: 250 ml beaker Thermometer 5 large test tubes Bunsen, tripod and gauze mat Dropper Metal tongs Graduated cylinder (10 ml) 5 ml sodium dichromate solution [Na2Cr2O7] 0.1 mol/L 5 ml sulfuric acid [H2SO4] 6 mol/L 2 ml potassium permanganate solution [KMnO4] 0.01 mol/L 4 pieces of sodium 6 ml ethanol [CH3CH2OH] 6 ml 2-methyl-2-propanol [(CH3)3COH] 6 ml 1-butanol [CH3CH2CH2CH2OH] 6 ml 2-butanol [CH3CH2CHOHCH3] PROCEDURE: Part A: Reaction of Alcohols with Oxidising Agents – Reaction with Dichromate Ion 1. 100 ml of water was heated to 80º in a 250 ml over a Bunsen. 2. The Bunsen was turned off. 3. 2 ml of ethanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol were placed into 4 separately labelled test tubes. 4. 4 ml of 0.1 mol/L Na2Cr2O7 and 2ml of 6 mol/L H2SO4 were mixed in another test tube. 5. 1 ml of the acidified Na2Cr2O7 was placed into each of the test tubes containing the alcohols, and these were put into the hot water bath for 5 minutes. 6. The mixtures were shaken occasionally to allow the aqueous and alcoholic phases to mix. 7. Results were obtained and recorded in a table, and the test tubes emptied into a beaker provided by the teacher and cleaned. Part B: Reaction of Alcohols with Oxidising Agents – Reaction with Permanganate Ion 1. 2 ml of ethanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol were placed into the 4 test tubes. 2. In a separate test tube 2 ml of 0.01 mol/L KMnO4 and 1 ml of 6 mol/L H2SO4 were mixed. 3. 3-5 drops of the acidified KMnO4 was added to each of the tubes containing the alcohols and the mixture was shaken gently. 4. Observations were made and recorded in a results table. Part C: Reaction of Alcohols with Sodium 1. 2 ml of ethanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol were placed into 4 clean test tubes and a single piece of sodium added. 2. A lighted taper was held in each test tube and the ‘pop’ test was initiated. 3. All observations concerning the sodium’s disintegration were made and recorded. RESULTS: Part A: Alcohol Observations Ethanol plus dichromate ionNa2Cr2O7+H2SO4 · Originally (before heat) a clear liquid, changed to olive green colour and then to dark blue· After heat, liquids were layered · Dense, dark blue/green liquid settled on bottom· Clear, water-like liquid on top· Liquids did not mix, even when shaken· Emitted a smell that was strong but not as powerful as the others 1-butanol · Before heat – liquid changed from clear to dark blue .· After heat liquids became layered.· Clear liquid on top with a dense, aqua green liquid on bottom.· Liquids did not mix at all.· Strong, overpowering ‘chloriney’ smell was given off.
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