Question

In the presence of peroxide, $HCl$ and $HI$ do not give anti-Markownikoff's addition of alkenes because:

• A. One of the step is endothermic in both $HCl$ and $HI$
• B. Both $HCl$ and $HI$ are strong acids
• C. $HCl$ is oxidising and $HI$ is reducing
• D. All the steps are exothermic in case of $HCl$ and $HI$

Answer 1

The correct option is A One of the step is endothermic in both $HCl$ and $HI$

Anti-Markownikoff's addition is possible only in case of $HBr$ and not in $HCl$ and $HI$. In $HBr$ both the chain initiation and chain propagation steps are exothermic, while in $HCl$ first step is exothermic and second step is endothermic and in $HI$ no step is exothermic. Hence, $HCl$ and $HI$ do not undergo anti-Markownikoff's reaction.