[bryceb]

what would you look for in an IR spectrum to support that an esterification reaction went to completion?
Can you use melting point as a method for analysis for esters?

[Babcock_Hall]

It is a forum rule (see red link above) that you must provide your answer or thoughts first, before we can help you.  However, I will provide a hint with respect to IR: think in terms of functional groups.

[wildfyr]

Honestly... IR is just plain not a good way to ensure complete conversion of any functional group. I would try very hard not to depend entirely on it in real research.

[rolnor]

TLC is possible in this case.

[hollytara]

"Esterification" is a pretty broad term - is it alcohol and acid (Fischer), alcohol and acid chloride, alcohol and anhydride? 

If it is Fischer - not going to completion anyway. 

For alcohol/acid chloride reactions... if done stoichiometrically (1:1), the alcohol hydroxyl ought to be gone in IR.  The carbonyl will shift  but it can be hard to be sure .

Alcohol and anhydride - side product is carboxylic acid and this makes both hydroxyl and carbonyl hard to interpret. 

There are some reactions where IR is a good quick diagnostic, but esterification isn't a very good example.

[OrganicDan96]

NMR is probably the best technique here

[Babcock_Hall]

For students answering questions like this on quizzes or tests, my advice is to focus on the changes in the functional groups, both those lost and those gained.  For NMR one might have to look at one or two bonds removed from the atoms that are undergoing covalent changes.