1. (4 pts) By what mechanism do primary halides react when treated with a nucleophile?     S_N2

Give two reasons why this mechanism is operative instead of the other possibility:

1.        There is no steric hindrance to backside attack by a nucleophile       .

2.        A primary carbocation resulting from departure of the halide (which would occur with S_N1) is extremely unstable      .

If the halogen is bonded to a chiral center, what is the fate of this chiral center (remains the same, inverts, racemizes, etc.) when undergoing substitution via this mechanism?       undergoes inversion     .

2. (6 pts) Complete the following reactions. If more than one product is formed, draw only the major one.