In the given reaction `C_6H_5-CH=CH-CH_3+HCl rarr[X]` [X] will be

Options

A. `C_6H_5-overset(Cl) overset(|)(CH)-CH_2-CH_3`
B. `C_6H_5-CH_2-overset(Cl)overset(|)(CH)-CH_3`
C. `Cl-C_6H_4-CH=CH-CH_3`
D. `C_6H_5-CH=CH-CH_2Cl`

Answer

To determine the product [X] from the reaction of C₆H₅-CH=CH-CH₃ with HCl, we can follow these steps:

### Step 1: Identify the Reactants
The reactant is C₆H₅-CH=CH-CH₃, which consists of a phenyl group (C₆H₅) attached to a propene structure (CH=CH-CH₃).

### Step 2: Understand the Reaction Mechanism
When HCl is added to an alkene, it typically undergoes an electrophilic addition reaction. According to Markovnikov's rule, the hydrogen (H⁺) will add to the carbon with more hydrogen atoms, while the chlorine (Cl⁻) will add to the other carbon.

### Step 3: Analyze the Double Bond
In the structure CH=CH-CH₃, both carbons involved in the double bond (the first carbon and the second carbon) have the same number of hydrogen atoms (one hydrogen each). Therefore, we cannot directly apply Markovnikov's rule here.

### Step 4: Consider the Two Possible Carbocations
1. **First Possibility**: If H⁺ adds to the first carbon (C₆H₅-CH), a carbocation is formed on the second carbon (C=CH-CH₃).
2. **Second Possibility**: If H⁺ adds to the second carbon (C=CH), a carbocation is formed on the first carbon (C₆H₅-CH⁺).

### Step 5: Stability of Carbocations
- The first carbocation (C₆H₅-CH⁺) is stabilized by resonance with the phenyl group. This delocalization of charge makes it more stable.
- The second carbocation (C=CH-CH₃⁺) is less stable because it does not have resonance stabilization.

### Step 6: Determine the Major Product
Since the first carbocation is more stable due to resonance, the Cl⁻ will attack the more stable carbocation (C₆H₅-CH⁺). Therefore, the product formed will be:

\[ \text{C}_6\text{H}_5\text{-CHCl-CH}_2\text{-CH}_3 \]

### Conclusion
The product [X] from the reaction C₆H₅-CH=CH-CH₃ + HCl is C₆H₅-CHCl-CH₂-CH₃.

### Final Answer
\[ [X] = \text{C}_6\text{H}_5\text{-CHCl-CH}_2\text{-CH}_3 \]

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