[(l-Bromo-l-methyl)ethyl]benzene, shown in the margin, undergoes solvohsis in a unimolecular, strictly first-order process. The reaction rate for [RBr] = 0.1 M RBr in 9:1 acetone: water is measured to be 2 × 10-4 mol L-1s-1.
(a) Calculate the rate constant k from these data. What is the product of this reaction?
(b) In the presence of 0.1 M LiCl, the rate is found to increase to 4 × 10-4 mol L-1s-1, although the reaction still remains strictly first order. Calculate the new rate constant kLiCI and suggest an explanation
(c) When 0.1 M LiBr is pas ent instead of LiCl, the measured rale drops to 1.6 × 10-4 mol L-1s-1. Explain this observation, and write the appropriate chemical equations to describe the reactions.