The Cannizzaro reaction is a redox disproportionation reaction that occurs between two molecules of an aldehyde, one of which is reduced to an alcohol while the other is oxidized to a carboxylic acid. This reaction is facilitated by a strong base, typically hydroxide ions OH- . The reaction is named after its discoverer, Stanislao Cannizzaro.For the Cannizzaro reaction involving formaldehyde HCHO and benzaldehyde C6H5CHO , the mechanism proceeds as follows:1. Nucleophilic attack: A hydroxide ion OH- acts as a nucleophile and attacks the carbonyl carbon of benzaldehyde, forming an alkoxide intermediate.C6H5CHO + OH- C6H5CH O- OH2. Hydride transfer: The alkoxide intermediate transfers a hydride ion H- to the carbonyl carbon of formaldehyde, reducing it to methanol CH3OH and generating a benzyl anion C6H5CH O- OH .C6H5CH O- OH + HCHO C6H5CH OH 2 + CH3OH3. Proton transfer: The benzyl anion abstracts a proton from either the solvent or another molecule of the alcohol product, forming the carboxylic acid product, benzoic acid C6H5COOH .C6H5CH OH 2 C6H5COOH + H2OOverall, the reaction can be summarized as:C6H5CHO + HCHO + OH- C6H5COOH + CH3OHFactors affecting the rate of the Cannizzaro reaction:1. Strength of the base: A stronger base, such as hydroxide ions, will increase the rate of the reaction due to its higher nucleophilicity, which facilitates the initial nucleophilic attack on the carbonyl carbon.2. Steric hindrance: Aldehydes with bulky substituents near the carbonyl group may reduce the rate of the reaction due to steric hindrance, which makes it more difficult for the nucleophile to approach and attack the carbonyl carbon.3. Electronic effects: Electron-donating groups on the aromatic ring of benzaldehyde can decrease the rate of the reaction by making the carbonyl carbon less electrophilic, while electron-withdrawing groups can increase the rate by making the carbonyl carbon more electrophilic.4. Temperature: As with most chemical reactions, an increase in temperature will generally increase the rate of the Cannizzaro reaction due to the increased kinetic energy of the reacting molecules.5. Concentration: Higher concentrations of the reactants aldehyde and base will generally lead to a faster reaction rate due to the increased frequency of collisions between the reacting species.