Question

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

• A. One of the steps is endothermic in HCl and HI
• B. Both HCl and HI are strong acids
• C. HCl is oxidizing and the HI is reducing
• D. All the steps are exothermic in HCl and HI

Answer 1

Answer: (A)

Anti-Markownikoff addition is possible only in case of $HBr$ and not in $HCl$ and $HI$. In $HBr$ both the chain initiation and 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 addition.