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3.(14 pt) The following equation shows the bromination  of methane:

1) Propose a mechanism (initiation and propagation steps) to account for the product formation.
Label the steps as A, B, C

…

 and calculate the 

D

H

°

 for each step.

See chlorination of methane discussed in the lecture notes and textbook.

2) Draw an energy diagram (using the 

D

H

°

 for each step to set appropriate energy levels) for the two

propagation

 steps, and decide which step is more likely the rate-determining step?  (label this step as

rds)

see the textbook for chlorination of methane and apply it to this case.

energy

reaction coordinate (progress)

CH

4

     +      Br

2

CH

3

Br     +     HBr

light