In the adddition of `HBr` to propene in the absence of peroxides, the first step involves the addition of-s

Options

A. `H^(+)`
B. `Br^(-)`
C. `H^(+)`
D. `Br^(+)`

Answer

To solve the question regarding the addition of HBr to propene in the absence of peroxides, we can break down the process step by step.

### Step-by-Step Solution:

1. **Understanding the Reaction**: The addition of HBr to propene (C3H6) is an example of an electrophilic addition reaction. In this reaction, HBr will add across the double bond of propene.

2. **Identifying the Electrophile**: In the absence of peroxides, HBr dissociates into H⁺ (a proton) and Br⁻ (bromide ion). The H⁺ ion acts as the electrophile that will first attack the alkene.

3. **Markovnikov's Rule**: Since propene is an unsymmetrical alkene, we apply Markovnikov's rule. This rule states that when HX (where X is a halogen) adds to an unsymmetrical alkene, the hydrogen atom (H) will attach to the carbon with the greater number of hydrogen atoms already attached (the less substituted carbon), while the halide (Br) will attach to the more substituted carbon.

4. **Formation of the Carbocation**: When H⁺ adds to propene, it will attach to the terminal carbon (C1), leading to the formation of a carbocation at the more substituted carbon (C2). This results in a secondary carbocation, which is more stable than a primary carbocation.

5. **Nucleophilic Attack**: In the next step, the Br⁻ ion will attack the positively charged carbon of the carbocation. This results in the formation of 2-bromopropane as the final product.

6. **Final Product**: The overall reaction can be summarized as:
\[ \text{C3H6} + \text{HBr} \rightarrow \text{C3H7Br} \quad (\text{2-bromopropane}) \]

### Conclusion:
Thus, the first step in the addition of HBr to propene involves the addition of H⁺ (option 1).

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