Under appropriate conditions, (S)-1-bromo-1-fluoroethane reacts with sodium methoxide to...

Under appropriate conditions, (S)-1-bromo-1-fluoroethane reacts with sodium methoxide to givepure (S)-1-fluoro-1-methoxyethane.

(a) Why is bromide rather than fluoride replaced?

(b) Draw perspective structures (as shown on the previous page for 2-bromobutane) for thestarting material, the transition state, and the product.

(c) Does the product show retention or inversion of configuration?

(d) Is this result consistent with reaction by the S_N2 mechanism?