What is the major organic product formed when 1-bromo-4-chlorobutane is reacted with exactly 1 equivalent of KNO ₂ ?

Step-by-step solution

The substrate, 1-bromo-4-chlorobutane, contains two primary halogens: bromine and chlorine. Bromide is a better leaving group than chloride because the C-Br bond is weaker than the C-Cl bond. When exactly 1 equivalent of a nucleophile is used, substitution will occur preferentially at the carbon bearing the bromine atom. The reagent KNO ₂ is an ionic compound and provides the nitrite ion (NO ₂^- ) in solution. The nitrite ion is an ambidentate nucleophile. Attack occurs predominantly through the more electron-rich