Explain why all efforts to synthesize a carboxylic acid containing the isotope oxygen-18 at only the carbonyl oxygen fail and yield instead a carboxylic acid in which the labeled oxygen is distributed equally between both oxygens of the carboxy group. (*O = ¹⁸O)

Transcribed Image Text:

*O R-C-OH *O || R-C-OH + R-C-OH (50% of label on each oxygen)