The synthesis of Alkyl fluoride is best carried through:

Swarts Reaction

The correct answer is Option (2) → Swarts Reaction

Preparation of alkyl fluorides is not easy through simple substitution reactions because fluoride ion is a poor nucleophile in protic solvents. Hence, specific methods are used where halogen exchange takes place using metal fluorides.

Option 1: Free radicals

Free radical halogenation is mainly useful for chlorination and bromination of alkanes. Fluorination through free radicals is highly explosive and uncontrollable due to the extreme reactivity of fluorine. Hence, this method is not suitable for controlled preparation of alkyl fluorides.

Option 2: Swarts Reaction

Swarts reaction is specifically used to prepare alkyl fluorides from alkyl chlorides or bromides by heating them with metallic fluorides such as $AgF, Hg_2F_2, SbF_3$, etc. It is the most reliable and standard laboratory method for synthesizing alkyl fluorides.

Option 3: Sandmeyer Reaction

Sandmeyer reaction is used to replace diazonium group in aromatic compounds with Cl, Br, or CN using copper salts. It is not applicable for preparing alkyl fluorides and mainly works for aromatic systems.

Option 4: Finkelstein Reaction

Finkelstein reaction is used for preparing alkyl iodides from alkyl chlorides or bromides using NaI in acetone. It involves halogen exchange but does not produce alkyl fluorides.