Question

Reactivity of alkyl halides towards SN₁ nucleophilic substitution reaction is:

• A. 3^o > 2^o > 1^o
• B. 3^o < 1^o < 2^o
• C. 3^o < 2^o < 1^o
• D. 2^o < 1^o < 3^o

Answer 1

The correct option is A

3^o > 2^o > 1^o

Reactivity of alkyl halides towards SN₁ nucleophilic substitution reaction is 3^o > 2^o > 1^o because in SN₁ nucleophilic reaction , the first and the slow step is the formation of a carbocation. Tertiary carbocation is more stable than a secondary carbocation which is more stable than a primary carbocation. Greater the stability of the carbocation, greater will be the ease of formation of carbocation, and hence faster will be the rate of the reaction.