Chemistry unit 8

An ester R-C(=O)-O-R′ is hydrolysed to a carboxylic acid and an alcohol R′OH. Researchers compare two possible pathways. In pathway I, the acyl C-O bond between the carbonyl carbon and the ester oxygen breaks; the original ester oxygen remains with R′. In pathway II, the O-R′ bond breaks; the original ester oxygen remains with the acid. A star denotes an oxygen isotope label. Assume no oxygen exchange after reaction and no isotope effect on reaction rate. Water supplies the oxygen needed to replace the broken linkage.