When a haloalkane reacts with aqueous KOH, what is the main product?

When a haloalkane reacts with aqueous KOH, the primary reaction that occurs is one in which the hydroxide ion (OH⁻) from KOH acts as a nucleophile. This nucleophile attacks the carbon attached to the halogen, leading to the substitution of the halogen atom by the hydroxyl group, forming an alcohol. This reaction is a type of nucleophilic substitution, commonly referred to as an S_N2 reaction when the haloalkane is primary or an S_N1 reaction for tertiary haloalkanes.

The use of aqueous KOH specifically promotes the formation of the alcohol because the aqueous environment ensures that hydroxide ions are sufficiently present to facilitate this direct substitution. It is important to recognize that competing reactions, such as elimination to form alkenes (dehydrohalogenation), are less favored in this case because the presence of water stabilizes the formation of the alcohol product.

In summary, the main product of the reaction between a haloalkane and aqueous KOH is an alcohol, due to the nucleophilic substitution mechanism that is favored in this aqueous environment.