Question

do esterification reactions have high or low yields? and why is this?

Answer 1

The typical yield is about 70% and much of this is due to the fact that an esterification reaction is the reverse of hydrolysis of an ester. Thus, esterifications are an equilibrium reactions in which k gives a yield of about 70% or so. Increasing the alcohol or removing the water increases the yield of the ester. Here is a site that gives other information about the mechanism.
http://en.wikipedia.org/wiki/Esterification