Answer:
Explained
Explanation:
In the experiment, an (18)O-labelled alcohol R('18)OH is used with normal unlabeled carboxylic acid RC(16)O2H:
The esterification reaction is:
(note: the bracketed values are atomic masses)
RC(16)O_2H + R'(18)OH => RC16O18OR' + H_2(16)O
Since the alcohol is the nucleophile in this nucleophilic substitution reaction, it adds to the carbonyl group of the carboxylic acid and the (18)O atom becomes incorporated into the ester product, while the (16)OH group of the carboxylic acid is expelled as H_2(16)O.
By using mass spectroscopy to measure the mass of the ester and water products, it can be shown that each ester molecule contains one (18)O atom and one (16)O atom, while the water molecules contains only (16)O atoms.
This would prove unequivocally that the ester contains one O atom from the carboxylic acid and one O atom from the alcohol, while the water contains only O atoms from the carboxylic acid.