See image — Aldehydes Ketones and Carboxylic Acids Chemistry Question

💡 Solution & Explanation

Concept: The Cannizzaro reaction occurs with aldehydes that have no alpha-hydrogen atoms. When treated with concentrated NaOH, such aldehydes undergo a disproportionation reaction in which one molecule is oxidized to a carboxylate and another is reduced to an alcohol. o-Phthalaldehyde (benzene-1,2-dicarbaldehyde) has no alpha-hydrogens on either aldehyde group, so it undergoes the Cannizzaro reaction. Step 1: Identify the substrate. o-Phthalaldehyde has two aldehyde groups on adjacent positions of a benzene ring. Neither CHO group has alpha-hydrogens. Step 2: Apply the intramolecular Cannizzaro reaction. Because both aldehyde groups are on the same molecule and positioned ortho to each other, the reaction can occur intramolecularly. One CHO is oxidized to COO- (carboxylate) and the other CHO is reduced to CH2OH (alcohol), all within the same molecule. Step 3: Determine the product. The intramolecular Cannizzaro reaction on o-phthalaldehyde gives 2-(hydroxymethyl)benzoate: one ortho group becomes CH2OH and the other becomes COO-. This corresponds to option (c). Step 4: Eliminate other options. - Option (a): CH(OH)2 groups would result from hydration of aldehydes, not a Cannizzaro reaction with conc. NaOH and heat. - Option (b): Isobenzofuran would require cyclization/dehydration, not typical of Cannizzaro conditions. - Option (d): Both groups becoming COO- would require full oxidation of both aldehydes, which is not how Cannizzaro works (it requires one oxidation and one reduction). Therefore, the correct answer is C.