Question

Part II. Competing nucleophiles with t-butyl alcohol 1. The composition of the product mixture is analyzed based on refractive index measurem. At 20.0 °C, the refractive index of puret-butyl chloride is 1.3877 and that of pure 1-buty bromide is 1.4280. One previous student determined the refractive index of his product mixture to be 1.4250 at 20.0 °C. Assume a linear relation between the refractive index and the molar composition of the mixture. Calculate the molar percentages of t-butyl chloride and/-butyl bromide in this student's mixture. Hint: Make a plot of refractive index - vs. molar percentage of t-butyl bromide (x-cris) using the refractive indexes of pure i-buy chloride and pure l-butylbromide. Find the mathematical relationship between refractive index and molar percentage of bromide. 2. Based on the result from question #1, determine which one is a better nucleophile, Br or CT. Explain what causes their different nucleophilicity in complete sentences. 3. Why is concentrated sulfuric acid used in this reaction? 4. Write the complete stepwise reaction mechanism accounting for the conversion from t-butyl alcohol tor-butyl bromide. Show structures of all intermediates. Use curved arrows to show the electron movement at each step. Don't forget the role of sulfuric acid. Sw Reactions (Revised on 11/20/2014) Page 5 of 5

Answer 1