Chapter 6.12, Problem 6.21P

Under appropriate conditions (S)-1-bromo-1-fiuoroethane reacts with sodium methoxide to give pure (S)-1-fluoro-1-methoxyethane.

$\begin{array}{cccc}{\text{CH}}_{\text{3}}\text{CHBrF +}& {\text{NaOCH}}_{\text{3}}\to & {\text{CH}}_{\text{3}}{\text{CHFOCH}}_{\text{3}}+& \text{NaBr}\\ (S)& & (S)& \end{array}$

1. a. Why is bromide rather than fluoride replaced?
2. b. Draw perspective structures (as shown on the previous page for 2-bromobutane) for the starting material the transition state, and the product.
3. c. Does the product show retention or inversion of configuration?
4. d. Is this result consistent with reaction by the S_N2 mechanism?