Nucleophilic additions are chemical reactions where a nucleophile, a species with a high electron density, attacks an electrophile, which is electron-deficient. This process typically occurs in carbonyl compounds, such as aldehydes and ketones, where the carbon atom of the carbonyl group is particularly susceptible to nucleophilic attack. During the reaction, the nucleophile donates a pair of electrons to the electrophilic carbon, forming a new bond. This results in the conversion of the carbonyl group into an alcohol or other functional groups, depending on the nucleophile used. Common nucleophiles include hydroxide ions and grignard reagents.