Converting a secondary alkyl halide into a secondary alcohol

[PStudent111]

I was reviewing for the MCAT and one of the examples given for converting a secondary alkyl halide into an alcohol was:

R₂H-Br -> R₂H-OH

1. RCO₂-
2. OH^-

In terms of the mechanism, what is the role of RCO₂-?

 

[Yanick]

Is the labeling of reagents 1 and 2 supposed to imply sequential reactions? Meaning is this recipe meant to be all done in one vessel?

Can you give us a guess about the mechanism of this transformation?