For the theoretical reaction A + C = F, the reaction mechanism was determined to be

A + B = D
C + D = E
E = B + F

what is the rate law for the overall reaction?

To determine the rate law for the overall reaction, we can follow these general steps:

1. Identify the slow (rate-determining) step in the reaction mechanism.
2. Write the rate law expression for the slow step.
3. If there is a species (an intermediate) in the rate law that does not appear in the overall balanced reaction, substitute the intermediate by another elementary reaction expression.

Assuming that the reaction mechanism provided has only one slow step, we need to know which one it is. However, information regarding which step is the slow step is not provided. Please provide which step is the slow step so that I can help you determine the rate law for the overall reaction.