Question

The reaction of propene with $$\text{HOCl }\left(\text{C}{\text{l}}_{\text{2}}\text{ + }{\text{H}}_{\text{2}}\text{O}\right)$$ proceeds through the intermediate:
A.$\text{C}{\text{H}}_3-\text{C}{\text{H}}^{+}-\text{C}{\text{H}}_2-\text{Cl}$
B.$\text{C}{\text{H}}_3-\text{CH}\left(\text{OH}\right)-{\text{CH}}_2^{+}$
C.$\text{C}{\text{H}}_3-\text{CH}\left(\text{Cl}\right)-{\text{CH}}_2^{+}$
D.$\text{C}{\text{H}}_3-\text{C}{\text{H}}^{+}-\text{C}{\text{H}}_2-\text{OH}$

Answer 1

Hint: The formation of carbocation provides the intermediate stage which can be observed when positively charged chlorine atom attacks on propene.The reaction of propene with $$\text{HOCl}$$ in the presence of $$\text{C}{\text{l}}_{\text{2}}\text{ + }{\text{H}}_{\text{2}}\text{O}$$ is an addition reaction. $$\text{HOCl}$$ contains $\text{O}{\text{H}}^{-}$ and $\text{C}{\text{l}}^{+}$.

Step by step answer: The structure of propene is $\text{C}{\text{H}}_{\text{3}}-\text{CH}=\text{C}{\text{H}}_{\text{2}}$. Propene reacts with $$\text{HOCl}$$ as follows:

The $$\text{HOCl}$$ contains $\text{O}{\text{H}}^{-}$ and $\text{C}{\text{l}}^{+}$.
In the first step of the reaction, the positively charged $\text{C}{\text{l}}^{+}$ attacks the carbon-carbon double bond. This results in formation of a carbocation intermediate $\text{C}{\text{H}}_3-\text{C}{\text{H}}^{+}-\text{C}{\text{H}}_2-\text{Cl}$.
In the second step of the reaction, the nucleophile $\text{O}{\text{H}}^{-}$ attacks the positively charged carbon atom. The final product obtained is $\text{C}{\text{H}}_3-\text{CH}\left(\text{OH}\right)-\text{C}{\text{H}}_2-\text{Cl}$.
Thus, the reaction of propene with $$\text{HOCl }\left(\text{C}{\text{l}}_{\text{2}}\text{ + }{\text{H}}_{\text{2}}\text{O}\right)$$ proceeds through the intermediate $\text{C}{\text{H}}_3-\text{C}{\text{H}}^{+}-\text{C}{\text{H}}_2-\text{Cl}$.

Thus, the correct option is (A) $\text{C}{\text{H}}_3-\text{C}{\text{H}}^{+}-\text{C}{\text{H}}_2-\text{Cl}$.

Additional Information: The reaction in which one molecule combines with another molecule to form a larger molecule is known as an additional reaction. No products are eliminated in the addition reaction.
There are two types of addition reactions:
Electrophilic addition reaction: In electrophilic addition reaction, a positively charged species known as electrophile gets added to a molecule.
Nucleophilic addition reaction: In nucleophilic addition reaction, a negatively charged species known as nucleophile gets added to a molecule.
The product formed in the reaction is 1-chloropropan-2-ol. 1-chloropropan-2-ol is an alcohol. Thus, the reaction is a preparation reaction of alcohol.

Note: A positively charged carbon atom is known as a carbocation.
When a carbon atom carrying a positive charge is attached to only one alkyl group it is known as a primary carbocation. Thus, $\text{C}{\text{H}}_3-\text{CH}\left(\text{Cl}\right)-{\text{CH}}_2^{+}$ is a primary carbocation.
When a carbon atom carrying a positive charge is attached to two other alkyl groups it is known as a secondary carbocation. Thus, $\text{C}{\text{H}}_3-\text{C}{\text{H}}^{+}-\text{C}{\text{H}}_2-\text{Cl}$ is a secondary carbocation.
A secondary carbocation is more stable than the primary carbocation. Thus, $\text{C}{\text{H}}_3-\text{C}{\text{H}}^{+}-\text{C}{\text{H}}_2-\text{Cl}$ is formed as an intermediate.