Which aromatic compound is obtained when noctane undergoes catalytic hydroforming (Aromatization ) on heating with `Al_(2)O_(3) + Cr_(2)O_(3)`.

Options

A. ethyl benzene
B. m-Xylene
C. o-Xylene
D. p-Xylene

Answer

To determine which aromatic compound is obtained when n-octane undergoes catalytic hydroforming (aromatization) on heating with Al2O3 + Cr2O3, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Starting Compound**:
The starting compound is n-octane, which has the molecular formula C8H18. It is a straight-chain alkane with eight carbon atoms.

2. **Understand the Process of Aromatization**:
Aromatization is the process of converting acyclic compounds (like alkanes) into aromatic compounds (like benzene) through dehydrogenation. This involves the removal of hydrogen atoms.

3. **Determine the Reaction Conditions**:
The reaction occurs in the presence of a catalyst (Al2O3 + Cr2O3) at high temperatures (around 723 K). This facilitates the dehydrogenation process.

4. **Calculate the Dehydrogenation**:
For n-octane (C8H18), we need to remove hydrogen atoms to form an aromatic compound. The general reaction for aromatization can be represented as:
\[ C_nH_{2n+2} \rightarrow C_nH_n + \text{H}_2 \]
For n-octane (C8H18), we can remove hydrogen to form a compound with a lower hydrogen count.

5. **Form the Aromatic Compound**:
Upon dehydrogenation, the product will be an aromatic compound. The most stable aromatic compound that can be formed from n-octane is **benzene (C6H6)**. However, since we are starting with C8H18, we can also consider the possibility of forming **ortho-xylene (C8H10)**, which has two methyl groups on the benzene ring.

6. **Final Products**:
The final products of the reaction will be:
- Benzene (C6H6)
- Evolved hydrogen gas (H2)
- Ortho-xylene (C8H10)

### Conclusion:
The aromatic compound obtained from the catalytic hydroforming of n-octane is **ortho-xylene (C8H10)**.