The best method to prepare neopentyl chloride is :-

• A) (C₃H₇)CCH₂OH ⟶ PC₅, Δ
• B) (C₃H₇)CCH₂OH ⟶ HCl, Δ
• C) (C₃H₇)CCH₂OH ⟶ SoCl₂, pyridine
• D) (C₃H₇)CCH₃ ⟶ Cl₂, hν Δ

To prepare neopentyl chloride, the most effective method is option C: (C₃H₇)CCH₂OH ⟶ SoCl₂, pyridine. This reaction involves converting the alcohol (C₃H₇)CCH₂OH into neopentyl chloride using thionyl chloride (SoCl₂) in the presence of pyridine, which acts as a base. This method is preferred due to its efficiency and the mild conditions required.

Why This Method Works

Thionyl chloride is a commonly used reagent for converting alcohols to alkyl chlorides. The reaction proceeds smoothly, producing neopentyl chloride with minimal side products.

Other Options Explained

• A) (C₃H₇)CCH₂OH ⟶ PC₅, Δ: This method is less common and may lead to multiple products.
• B) (C₃H₇)CCH₂OH ⟶ HCl, Δ: While possible, this method is not as efficient as using thionyl chloride.
• D) (C₃H₇)CCH₃ ⟶ Cl₂, hν Δ: This involves free radical chlorination, which can lead to a mixture of products rather than a pure compound.

In summary, option C is the best choice for synthesizing neopentyl chloride due to its reliability and straightforward procedure.