Explain the mechanism of a unimolecular nucleophilic substitution $(S_N1)$ reaction with a suitable example.
(N/A) The $S_N1$ reaction between tert-butyl bromide and hydroxide ion $(OH^-)$ yields tert-butyl alcohol.
$(CH_3)_3C-Br + OH^- \longrightarrow (CH_3)_3C-OH + Br^-$
Characteristics of $S_N1$ reaction:
$(a)$ Unimolecular kinetics: The rate of reaction depends only on the concentration of the substrate,tert-butyl bromide.
$(b)$ Nucleophilic substitution: The leaving group $Br^-$ is replaced by the nucleophile $OH^-$.
$(c)$ Two-step process: $S_N1$ reactions proceed in two steps.
Step $I$ (Slow step): The $C-Br$ bond undergoes heterolytic cleavage to form a carbocation $(CH_3)_3C^+$ and a bromide ion $Br^-$. This is the rate-determining step.
Step $II$ (Fast step): The nucleophile $OH^-$ attacks the carbocation to form the final product,tert-butyl alcohol.
$(CH_3)_3C-Br + OH^- \longrightarrow (CH_3)_3C-OH + Br^-$
Characteristics of $S_N1$ reaction:
$(a)$ Unimolecular kinetics: The rate of reaction depends only on the concentration of the substrate,tert-butyl bromide.
$(b)$ Nucleophilic substitution: The leaving group $Br^-$ is replaced by the nucleophile $OH^-$.
$(c)$ Two-step process: $S_N1$ reactions proceed in two steps.
Step $I$ (Slow step): The $C-Br$ bond undergoes heterolytic cleavage to form a carbocation $(CH_3)_3C^+$ and a bromide ion $Br^-$. This is the rate-determining step.
Step $II$ (Fast step): The nucleophile $OH^-$ attacks the carbocation to form the final product,tert-butyl alcohol.
Explore More
Similar Questions
Arrange the compounds of each set in order of reactivity towards $S_{N}2$ displacement:
$(i)$ $2-Bromo-2-methylbutane$,$1-Bromopentane$,$2-Bromopentane$
$(ii)$ $1-Bromo-3-methylbutane$,$2-Bromo-2-methylbutane$,$2-Bromo-3-methylbutane$
$(iii)$ $1-Bromobutane$,$1-Bromo-2,2-dimethylpropane$,$1-Bromo-2-methylbutane$,$1-Bromo-3-methylbutane$.
$(i)$ $2-Bromo-2-methylbutane$,$1-Bromopentane$,$2-Bromopentane$
$(ii)$ $1-Bromo-3-methylbutane$,$2-Bromo-2-methylbutane$,$2-Bromo-3-methylbutane$
$(iii)$ $1-Bromobutane$,$1-Bromo-2,2-dimethylpropane$,$1-Bromo-2-methylbutane$,$1-Bromo-3-methylbutane$.
Easy
View SolutionThe set of compounds in which the reactivity of the halogen atom increases in the order is ..........
Difficult
View SolutionWhich among the following compounds has the highest boiling point?
When $32.25 \ g$ of ethyl chloride is dehydrohalogenated,it gives $50\%$ yield of alkene. What is the mass of the product in $g$? (Atomic mass of $Cl = 35.5$)
Medium
View SolutionWhich of the following compounds is most reactive towards $S_{N^1}$ reaction?
Difficult
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo