The addition of propene with HOCl proceeds via the addition of:

Options

A. `H^(+)` in the fisrst step
B. `Cl^(+)` in the first step
C. `OH^(-)` in the first step
D. `Cl^(+)` and OH– in a single step

Answer

To solve the question regarding the addition of propene with HOCl, we will analyze the mechanism of the reaction step by step.

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this reaction are propene (C3H6) and hypochlorous acid (HOCl).

2. **Protonation of HOCl**: In an acidic medium, HOCl can dissociate to produce H⁺ and Cl⁻. The H⁺ ion can protonate the double bond of propene, making it more electrophilic.

3. **Formation of Carbocation**: The double bond in propene can react with the Cl⁺ ion (which is generated from the dissociation of HOCl). The addition of Cl⁺ can occur at either of the carbon atoms involved in the double bond.

- If Cl⁺ attacks the terminal carbon (C1), a primary carbocation is formed.
- If Cl⁺ attacks the middle carbon (C2), a secondary carbocation is formed, which is more stable.

4. **Stability of Carbocations**: The secondary carbocation is more stable than the primary carbocation due to hyperconjugation and inductive effects. Therefore, the Cl⁺ will preferentially add to the middle carbon (C2) of propene.

5. **Formation of the Chloronium Ion**: When Cl⁺ adds to the double bond, it forms a cyclic chloronium ion intermediate. This intermediate involves a three-membered ring structure where the chlorine atom is positively charged.

6. **Nucleophilic Attack by Water**: The chloronium ion is then attacked by a nucleophile, which in this case is water (H2O). The oxygen atom of water has lone pairs of electrons and can attack the more substituted carbon (C2) of the chloronium ion.

7. **Deprotonation**: After the nucleophilic attack, a proton (H⁺) is lost from the oxygen atom of the water molecule, resulting in the formation of the final product.

8. **Final Product**: The final product of the reaction is 2-chloropropanol (CH3-CHOH-CH2Cl).

### Conclusion:
The addition of propene with HOCl proceeds via the formation of a chloronium ion and involves the addition of Cl⁺ first, followed by the attack of water.