Question

Lowest $p{K}_a$ is associated with Monobromination of $2$-methylbutane gives how many distinct isomers?

• A. One
• B. Two
• C. Three
• D. Four

Answer 1

Answer: (D)

Structure of $2$-methylbutane $C{H}_3-\underset{\stackrel{|}{C{H}_3}}{\mathrm{CH}}-C{H}_2-C{H}_3$ Since there are four different types of hydrogen, thus four types of isomers are obtained.
$\underset{\text{1-bromo - 2- methylbutane}}{Br-C{H}_2-\underset{\stackrel{|}{C{H}_3}}{\mathrm{CH}}-C{H}_2-C{H}_3};\underset{\text{2- bromo-2-methylbutane}}{C{H}_3-\underset{\stackrel{|}{C{H}_3}}{\stackrel{\underset{|}{\mathrm{Br}}}{C}}-C{H}_2-C{H}_3}$
$\underset{\text{2 - bromo - 3 - methylbutane}}{C{H}_3-\underset{\stackrel{|}{C}{H}_3}{\mathrm{CH}}-\stackrel{\underset{|}{B}r}{\mathrm{CH}}-C{H}_3};\underset{\text{1 - bromo-3-methylbutane}}{C{H}_3-\underset{\stackrel{|}{C{H}_3}}{\mathrm{CH}}-C{H}_2-C{H}_2-Br}$