Part A: 1. Solid product forms during the addition of the bleach solution. Why d
ID: 227698 • Letter: P
Question
Part A: 1. Solid product forms during the addition of the bleach solution. Why does the camphor precipitate out of solution as it forms? 2. After washing with aqueous sodium bicarbonate, a student carefully separated the two layers and added 5% sodium bisulfite solution to the organic layer. She noticed that only one layer was seen during this second wash. What happened? 3. A student dried the solution containing the product using sodium sulfate. He then evaporated off the methylene chloride without first decanting the solution off of the Na2SO4. What will this do to the percent yield of the reaction?Explanation / Answer
1. Conversion of borneol to camphor is an example for Jone’s oxidation. The oxidizing agent bleach (sodium hypochloride) converts secondary alcohol (borneol) to ketone (camphor). Jones’s reaction occurs in acidic aqueous media and camphor precipitate out of solution as it forms. The reason for precipitation of camphor is that it is insoluble in water. Water is polar and camphor is a nonpolar hydrocarbon. According to “like dissolves like” rule only polar solutes dissolve in polar solvents.
2. Sodium bisulphate will react with ketones and aldehydes to form addition product. That is why she couldn’t separate the layer.
3. Yield is calculated from weight of pure and dried product. In this case yield of the reaction will be higher than the actual yield. Since the final compound contains sodium sulphate also. She has to remove sodium sulphate completely to get the actual yield of the reaction.