Question

Choose the member of the given pair that will react faster by $S_{N}1$ mechanism.
$2$-bromo-$2$-methylbutane or $2$-bromo-$3$-methyl butane:

• A. $2$-bromo-$2$-methylbutane > $2$-bromo-$3$-methyl butane
• B. $2$-bromo-$2$-methylbutane < $2$-bromo-$3$-methyl butane
• C. $2$-bromo-$2$-methylbutane = $2$-bromo-$3$-methyl butane
• D. None of these

Answer 1

The correct option is A $2$-bromo-$2$-methylbutane > $2$-bromo-$3$-methyl butane

$2-$bromo−$2-$methylbutane will react faster by $S_{N}1$ mechanism than $2$−bromo−$3$−methylbutane.

$2$−bromo−$2$−methylbutane is tertiary alkyl halide and forms tertiary carbocation.$2$-bromo_$3$-methylbutane is secondary alkyl halide and forms secondary carbocation.

Tertiary carbocation is more stable and more easily formed than secondary carbocation.