Ncert Exercises & Solutions

Which of the following carbon marked with asterisk is expected to have greatest positive charge?

1. $* {CH}_{3} - {CH}_{2} - Cl$

2. $* {CH}_{3} - {CH}_{2} - {Mg}^{+} {Cl}^{-}$

3. $* {CH}_{3} - {CH}_{2} - Br$

4. $* {CH}_{3} - {CH}_{2} - {CH}_{3}$

Hint: consider inductive effect of substituents

Electronegativity of Cl, Br, C and Mg follows the order Cl>Br>C>Mg

* {CH}_{3} \to {CH}_{2} \to Cl

(- I - effect)

* {CH}_{3} \leftarrow {CH}_{2} \leftarrow {Mg}^{+} {Cl}^{-}

* {CH}_{3} \to {CH}_{2} \to Br

(- I - effect)

* {CH}_{3} - {CH}_{2} - {CH}_{3}

(+I-effect)

-I effect of Cl>Br

Hence,

{CH}_{3} - {CH}_{2} - Cl

has the greatest positive charge.