Lab Report - Experiment#10 - Questions 1. Sodium iodide is...

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Questions 1. Sodium iodide is soluble in acetone and water. Sodium bromide and sodium chloride are soluble in water but not in acetone. If the reaction tube is not dry, NaBr and NaCl exists in the reaction solution as ions and the reaction reaches the equilibrium so that alkyl iodide would not be produced. In acetone, NaBr and NaCl are removed as precipitate so that the alkyl iodide will be produced with addition of NaI. Sodium iodie in acetone reacts readily with other compounds undergoing SN1 reaction. To prevent forming unnecessary precipitate, reaction tube should be dry. The formation of the insoluble product drives the reaction to completion. 2. The reaction of 1-bromopropane with sodium iodide to give 1-iodopropane is endothermic. Transition state structure for endothermic reactions resembles the product, and the bond to the leaving group is nearly broken. In order to have good yield of product, among many factors that affect the rate of the reactions such as nucleophilicity and substrate, solvent and temperature can be adjusted in this case. Use of polar aprotic solvents such as acetone would bring a good yield of product because they accelerate SN2 reactons because the nucleophiles are well separated from their counterions but not tightly solvated (and make sure that tubes are dry as stated in question number 1). Also temperature or addition of heat fastens the rate of the reaction by quickly separating and forming the intermolecular force. 3. 2-bromopropane reacts with sodium iodide in acetone over 10 4 times faster than bromocyclopropane. And this can be explained by their transition state. In order to have secondary carbon to have Sn2 reaction, unhindered substrate is required since it is better to have leaving group accessible as possible and the incoming group can backside attack the substrate more easily. In 2-bromopropane, the leaving group is in the secondary carbon. This is difficult enough for nucleophilic attack, but bromocyclopropane is worse.
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Lab Report - Experiment#10 - Questions 1. Sodium iodide is...

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