The reaction `CH_2=CH-CH_3-HBr to CH_3CHBr -CH_3` is

Options

A. Nucleophilic reaction
B. Electrophilic reaction
C. Electrophilic reaction
D. Free radical addition

Answer

To solve the question regarding the reaction of propene (CH₂=CH-CH₃) with HBr to form 2-bromopropane (CH₃CHBrCH₃), we will analyze the process step by step.

### Step-by-Step Solution:

1. **Identify the Reactants and Products:**
- The reactant is propene (CH₂=CH-CH₃) and the product is 2-bromopropane (CH₃CHBrCH₃).
- The reaction involves the addition of HBr to the double bond of propene.

2. **Understand the Mechanism:**
- This reaction proceeds via an electrophilic addition mechanism. In electrophilic addition, an electrophile reacts with a nucleophile.

3. **Formation of Carbocation:**
- The double bond in propene acts as a nucleophile and attacks the electrophile H⁺ from HBr.
- This results in the formation of a carbocation intermediate. In this case, the more stable carbocation (secondary carbocation) is formed at the second carbon (CH₃-CH⁺-CH₃).

4. **Nucleophilic Attack:**
- The bromide ion (Br⁻), which is the nucleophile, then attacks the positively charged carbon of the carbocation.
- This results in the formation of 2-bromopropane (CH₃CHBrCH₃).

5. **Conclusion:**
- The overall reaction can be summarized as:
\[ CH_2=CH-CH_3 + HBr \rightarrow CH_3CHBrCH_3 \]
- This confirms that the reaction is an electrophilic addition reaction.

### Final Answer:
The reaction of propene with HBr to form 2-bromopropane is an **electrophilic addition reaction**.