Question

Select whether the following combinations of reactants will react by substitution $(S_{N^1}or{S}_{N^2}$ mechanism), elimination ($E_{1}or{E}_2$ mechanism).
$(C{H}_3{)}_{3}C-OH\underset{{25}^{0}C}{\overset{HBr48\%in{H}_{2}O}{\to }}$

• A. $S_{N^1}$
• B. $S_{N^2}$
• C. $E_1$
• D. $E_2$

Answer 1

The correct option is A $S_{N^1}$

t-butanol undergoes $S_{N}1$ (Nucleophilic substitution unimolar) when treated with acid.

$(C{H}_3{)}_{3}C-OH\underset{HBr48}{\overset{{25}^{\circ }C}{\to }}{H}_{3}C-C-Br$

The reaction involves the protonation of -OH group followed by formation of carbocation. Generation of $3^{\circ }$ cation is the rate determining step and is said to be unimolar i.e. $S_{N}1$.