Question

Rank the following molecules in order of reactivity for an Sn2 substitution reaction (1 = most reactive, 4 = least reactive). ~ Br you d ora usea H3C-ci

Answer 1

SN² is a type of nucleophilic substitution reaction SN² stands for substitution nucleophilic bimolecular It is a type of concerted mechanism which takes place in a single step without any intermediate formation. In this type of reaction the incoming nucleophile attacks the carbon atom directly attached to a halogen from back ride and leaving group (the halide ion that is a where can be ce, ber, I orf) leaves from other side The reaction takes place via a transition state. The mechanism of an SN² can be shown as: Nucleophile (Alkyl Halide) ه موا Nu-C- + X

Since in this mechanism, the attack of nucleophile occurs from the back ride on the carbon directly attached to the halogen, the presence of bulky groups around that carbon tends to hinder the approach of the incoming nucleophile. So more are the bulky groups present around the carbon bearing halogen atom, slower is the so? reaction. So the order of reactivity in Su² reactions isi Methye halide Primary Halide > Secondary Halide U > Tertiary alide -- A primary on i halide is where only one substituent other than hydrogens is attached to carbon bearing halogen a secondary or 2 halide contains two sulestituents and a tertiary or 3 halide has three sules tituants present)

wewe, 390 there this attached to carbon two other bevat om The structure is the Secondary Carbon ompound La secondary halede. This to carbon three is other other carbon attached atoms The structure Tertiary Carbon This compound is a tertiary halide, attached This to carbon is one carbon further atom - CH2 CH Cth-ce The primary carbon halide. It is a primary

♡ _thecace It is a simple methye halide as no substituents other than hydrogen are present. so the order of reactivity is до- и > Gay y ze (Methyl ( Primary (Secondary. (Tertiary Halide) Halide) Halide) Halide) ( وهي سموحد Most Reactive Least pun Reactive