The nucleophilic addition reaction of methanol with propanal involves the following steps:1. Protonation of the carbonyl oxygen: Methanol CH3OH acts as a weak acid and donates a proton H+ to the carbonyl oxygen of propanal CH3CH2CHO . This increases the electrophilicity of the carbonyl carbon, making it more susceptible to nucleophilic attack.2. Nucleophilic attack: The oxygen atom in methanol, which has a lone pair of electrons, acts as a nucleophile and attacks the electrophilic carbonyl carbon of protonated propanal. This results in the formation of an intermediate tetrahedral species.3. Deprotonation: The intermediate tetrahedral species loses a proton H+ to a nearby methanol molecule, which acts as a base. This step generates the final product and regenerates the methanol molecule.The product obtained from the nucleophilic addition reaction of methanol with propanal is 1-methoxypropan-2-ol CH3CH OCH3 CH2OH . This compound is also known as a hemiacetal, which is formed by the addition of an alcohol to an aldehyde.