`n-C_7H_16 underset"10-20 atm"overset(V_2O_5, 500^@C) A overset(Cl_2//hv)to B`
What is B in the above reaction ?

Options

A. Benzyl chloride
B. Benzal chloride
C. Hexachlorobenzene
D. Benzene hexachloride

Explanation

To determine the product B from the given reaction involving n-C₇H₁₆ (heptane), we can break down the process step by step.

### Step 1: Identify the Reactants
The reactant is n-C₇H₁₆ (heptane). Heptane is a straight-chain alkane with seven carbon atoms.

### Step 2: Understand the Reaction Conditions
The reaction occurs under the following conditions:
- Catalyst: V₂O₅ (Vanadium(V) oxide)
- Temperature: 500°C
- Pressure: 10-20 atm

### Step 3: Identify the First Reaction Product (A)
Under the influence of V₂O₅ at high temperature and pressure, heptane undergoes dehydrogenation and/or cracking, leading to the formation of aromatic compounds. The primary product formed is toluene (C₇H₈) due to the loss of hydrogen atoms.

### Step 4: Identify the Second Reaction with Chlorine
The product (A), which is toluene, then undergoes a chlorination reaction in the presence of chlorine (Cl₂) and ultraviolet light (hv). This reaction typically follows a free radical mechanism.

### Step 5: Determine the Product (B)
In the chlorination of toluene, the chlorine can replace one of the hydrogen atoms on the benzene ring. The most common product formed from this reaction is benzyl chloride (C₇H₇Cl), where a chlorine atom replaces a hydrogen atom on the carbon adjacent to the benzene ring.

### Conclusion
Thus, the product B in the above reaction is **benzyl chloride (C₇H₇Cl)**.

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