Question

The order of reactivity of halides towards $S_{N}1$ mechanism is

• A. benzyl $>$ allyl $>1^{∘}>2^{∘}>3^{∘}>Me$
• B. Me $>1^{∘}>2^{∘}>3^{∘}>$ allyl $>$ benzyl
• C. $3^{∘}>2^{∘}>1^{∘}>Me>allyl>$ benzyl
• D. benzyl $>$ allyl $>3^{∘}>2^{∘}>1^{∘}>Me$

Answer 1

Answer: (D)

The order of reactivity of halides towards $S_{N}1$ mechanism is
benzyl $>$ allyl $>3^{∘}>2^{∘}>1^{∘}>$ Me
$S_{N}1$ reaction is non-stereospecific and non-stereoselective as the attack of nucleophile is not specific and the products are a mixture of enantiomers.