Question

Which substituents have an electron-withdrawing and which have an electron-donating inductive effect

a${\mathbf{CH}}_{\mathbf{3}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{-}$

b$\mathbf{Br}\mathbf{-}$

c${\mathbf{CH}}_{\mathbf{3}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{O}\mathbf{-}$

Short answer

a. Electron-donating group.

b. Electron-withdrawing group.

c. Electron-withdrawing group.

Step-by-step solution

Electron-withdrawing group

The electron-withdrawing groups attract the electrons towards themselves. The most electronegative atoms act as electron-withdrawing groups

Electron-donating group

The electron-donating group donates electrons to the deficient atoms. The electrons can be donated by the groups which carry lone pair of electrons and the electrons can be donated by the sigma bonding.

Explanation

a. The${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}^{\text{-}}$ is an electron-donating group. The carbon donates its sigma electrons.

b. The Br is an electron-withdrawing group because it is an electronegative atom.

c. The${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{O}$ is an electron-withdrawing group because O is an electronegative atom.