What is correct order of $\mathrm{C}-\mathrm{X}$ bond strength in $\mathrm{CH}_{3}-\mathrm{X}$ ?

What is correct order of $\mathrm{C}-\mathrm{X}$ bond strength in $\mathrm{CH}_{3}-\mathrm{X}$ ?
  1. $\mathrm{CH}_{3} \mathrm{~F}>\mathrm{CH}_{3} \mathrm{Cl}>\mathrm{CH}_{3} \mathrm{Br}>\mathrm{CH}_{3} \mathrm{I}$
  2. $\mathrm{CH}_{3} \mathrm{~F}>\mathrm{CH}_{3} \mathrm{Br}>\mathrm{CH}_{3} \mathrm{Cl}>\mathrm{CH}_{3} \mathrm{I}$
  3. $\mathrm{CH}_{3} \mathrm{CI}>\mathrm{CH}_{3} \mathrm{Br}>\mathrm{CH}_{3} \mathrm{I}>\mathrm{CH}_{3} \mathrm{~F}$
  4. $\mathrm{CH}_{3} \mathrm{I}>\mathrm{CH}_{3} \mathrm{Br}>\mathrm{CH}_{3} \mathrm{Cl}>\mathrm{CH}_{3} \mathrm{~F}$

Solution

The size of halogen atom increases from $\mathrm{F}$ to $\mathrm{I}$, which increases the $\mathrm{C}-\mathrm{X}$ bond length. Larger the size, greater is the bond length and weaker is the bond formed. Hence the order of $\mathrm{C}-\mathrm{X}$ bond strength in $\mathrm{CH}_{3} \mathrm{X}$ is, $\mathrm{CH}_{3} \mathrm{~F}>\mathrm{CH}_{3} \mathrm{Cl}>\mathrm{CH}_{3} \mathrm{Br}>\mathrm{CH}_{3} \mathrm{I}$.

Asked in: MHT CET 2020 (16 Oct Shift 2)

Practice more Halogen Derivatives questions on Aicharya