Nucleophilic Addition Reaction

Nucleophilic Attack: A nucleophile attacks the electrophilic carbon atom of the polar carbonyl group from a direction approximately perpendicular to the plane of the $sp^2$ hybridised orbitals of the carbonyl carbon.
Hybridisation Change: The hybridisation of the carbonyl carbon atom changes from $sp^2$ to $sp^3$ during this reaction process.
Intermediate Formation: A tetrahedral alkoxide intermediate is produced as a result of the nucleophilic addition.