Question

You don’t have to tell me purpose. just where in procedure for each technique.

Section/Instructor SN2 Pre-lab (20 points) Answer on a separate piece of paper 1. (6 pts.) What is the purpose of the following experimental techniques and where in the procedure is each used? a. Heating under reflux b. Simple distillation c. Water wash d. Addition of COLD NAOH e. Saturated NaCl solution f. Addition of anhydrous sodium sulfate SN2 Reaction Procedure Set-Up: 100 mL RBF: 11.1 g NaBr, 10 mL of water, 10.0 mL 1- butanol. Thoroughly mix flask contents by swirling; cool in an ice-water bath In the HOOD. Slowly add 10 mL of conc. H,SO, with continuous swirling and cooling. Do not freeze. Add stir bar, remove from ice-water bath Return to lab bench. Set up for heating under reflux Reaction: Warm flask gently to dissolve salts. Heat under reflux for about 45 min. . Set up for simple distillation. Rapidly distill the mixture. Collect the distillate of water and 1-bromobutane in an ice-cooled receiver. Continue distillation until the distillate is clear and head temp is about 115 °C. (Note: At this point both H,SO, and HBr are co-distilling with water) Work-Up: Transfer distillate to sep funnel and add about 10 mL of water. Gently shake and vent funnel. Separate the layers Wash the organic layer sequentially with two 5 mL portions of cold 2M NaOH, 10 mL of water, and 10 mL of NaCld .Transfer the cloudy 1-bromobutane layer to a 50 mL Erlenmeyer flask; dry with anhydrous Na,So Isolation Transfer the crude 1-bromobutane to a clean, dry 25 mL RBF Short-path distillation: collect distillate in a tared vial on ice, (boiling point of greater than about 90°C). Analysis Weigh product, calculate percent yield Perform characterization tests Save sample for IR analysis Waste Stillpot residue: What is it? Place in waste jug, rinse flask with water to remove any residual residue, add water to jug Na,SO: Dispose of in waste labeled "halogenated Na,SO Characterization test tube contents in appropriate waste jug

Answer 1

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