Question

During halogenation of an alkane, the ease of replacement of hydrogen atoms follows the order:

Options

• 3° H - atom > 2° H - atom > 1° H - atom

• 2° H - atom > 3° H - atom > 1° H - atom

• 1° H - atom > 3° H - atom > 2° H - atom

• 1° H - atom > 2° H - atom > 3° H - atom

Answer 1

3° H - atom > 2° H - atom > 1° H - atom

Explanation:

During halogenation of alkanes, a hydrogen atom is replaced through a free radical substitution reaction.

The ease of replacement depends on the stability of the alkyl free radical formed after the removal of hydrogen.

Radical stability order:

3∘ radical > 2∘ radical > 1∘ radical