Question

The reaction of vinyl chloride with hydrogen iodide to give 1-chloro-1-iodoethane follows:

• A. Markovnikov's rule
• B. anti Markovnikov's rule
• C. Zaitsev rule
• D. none of these

Answer 1

The correct option is A Markovnikov's rule

Vinyl Chloride is written as $C{H}_2$$=$$CH\left(Cl\right)$. It reacts with hydrogen iodide that is $HI$ to give $C{H}_3$$-$$CH\left(Cl\right)I$.

$C{H}_2$$=$$CH\left(Cl\right)$ $+$ $HI$ $\to$ $C{H}_3$$-$$CH\left(Cl\right)I$

Markonikov rule states that, on addition of a $HX$ molecule (where $X$ is a halogen), to an alkene or alkyne, the Hydrogen atom of $HX$, is added to the carbon atom having the most number of Hydrogen atoms in the initial/starting alkene or alkyne.

Thus if Markonikov rule is to be followed, the Hydrogen atom of $HI$ must be added to the carbon atom of the alkene $C{H}_2$$=$$CH\left(Cl\right)$, where are 2 Hydrogen atoms. The product formed is $C{H}_3$$-$$CH\left(Cl\right)I$, which means the Hydrogen atom is attached to that carbon atom of the starting alkene, where there were two Hydrogen atoms initially.

Thus it is Markonikov rule.