Question

What is the major product of the above reaction?

• A. 1-chloro-2-methylbutane
• B. 2-chloro-2-methylbutane
• C. 2-chloro-3-methylbutane
• D. 1-chloro-3-methylbutane

Answer 1

The correct option is C 2-chloro-3-methylbutane

The major product of this reaction is decided by kinetic factor.
i.e., rate of chlorination $\propto$ k[H]
k $⟹$ $\stackrel{1^0}{x}\stackrel{2^0}{3.8x}\stackrel{3^0}{5x}$
so,
rate of attack on $1^0{C}_1=x\left[6\right]$
rate of attack on $1^0{C}_4=x\left[3\right]$
rate of attack on $2^0{C}_3=3.8x\left[2\right]=7.6x$
rate of attack on $3^0{C}_2=5x\left[1\right]$
hence , major product will be the one in which $Cl$ is substituted at $2^{0}C$
i.e.,