Identify the major product formed in the following reaction:

Step-by-step solution

The given reactant is 3,3-diphenyloxirane-2-carboxylic acid, which is a glycidic acid. Heating a glycidic acid results in thermal decarboxylation to form an aldehyde or a ketone. This is a characteristic reaction known as the Darzens glycidic ester condensation's final step. The mechanism involves the opening of the epoxide ring to form a stable carbocation. The C-O bond breaks such that the positive charge develops on the carbon bearing the two phenyl groups, as it is highly resonance-stabilized (benzhydryl-type c