KI in acetone, undergoes SN2 reaction with each of P, Q, R and S. The rates of the reaction vary as

Question

KI in acetone, undergoes SN2 reaction with each of P, Q, R and S. The rates of the reaction vary as <img class="img-fluid question-image" alt="Question" src="https://cdn.tardigrade.in/q/nta/c-xwrcqexkcqzskded.jpg" /> (A) P > Q > R > S (B) S > P > R > Q (C) P > R > Q > S (D) R > P > S > Q

Tardigrade Admin · Accepted Answer

SN2 reactions are through back side attack of attacking Nu- and not on the basis of stability of carbocation. Here less hindered site is more favourable for attack hence the correct order is <img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/c-xwrcqexkcqzstj76.jpg" />

Q. KI in acetone, undergoes $S_{N} 2$ reaction with each of P, Q, R and S. The rates of the reaction vary as

P > Q > R > S

S > P > R > Q

P > R > Q > S

R > P > S > Q

$S_{N} 2$ reactions are through back side attack of attacking $N u^{-}$ and not on the basis of stability of carbocation. Here less hindered site is more favourable for attack hence the correct order is

Q. KI in acetone, undergoes SN​2 reaction with each of P, Q, R and S. The rates of the reaction vary as