n-Octane when heated to 773 K under a pressure of 10-20 atm and in presence of a mixture of `Cr_2O_3, V_2O_5` and `Mo_2O_3` supported over `Al_2O_3` as catalyst, gives

Options

A. o-xylene
B. m-xylene
C. p-xylene
D. all the three

Explanation

To solve the problem of what n-octane produces when heated to 773 K under a pressure of 10-20 atm in the presence of a mixture of Cr₂O₃, V₂O₅, and Mo₂O₃ supported over Al₂O₃ as a catalyst, we can follow these steps:

### Step 1: Understanding the Reaction Conditions
- **Temperature**: 773 K
- **Pressure**: 10-20 atm
- **Catalyst**: Mixture of Cr₂O₃, V₂O₅, and Mo₂O₃ supported on Al₂O₃

### Step 2: Identifying the Type of Reaction
- The reaction conditions suggest that we are likely dealing with a catalytic process aimed at breaking down n-octane, which is an alkane. Under these conditions, we can expect either cracking or oxidation reactions.

### Step 3: Predicting the Products
- **Cracking**: This process involves breaking the carbon chains of n-octane into smaller hydrocarbons. Given the presence of the catalyst and the high temperature and pressure, we can expect the formation of smaller alkanes and possibly alkenes.
- **Oxidation**: The presence of metal oxides (Cr₂O₃, V₂O₅, Mo₂O₃) suggests that partial oxidation could occur, leading to the formation of alcohols, aldehydes, or carboxylic acids.

### Step 4: Conclusion on Products
- Based on the conditions and the nature of the catalyst, n-octane will likely yield a mixture of smaller hydrocarbons (like hexane, heptane) and possibly some oxidized products (like octanol or octanal).

### Final Answer
Under the given conditions, n-octane when heated to 773 K and under pressure with the specified catalyst will produce a mixture of smaller hydrocarbons and possibly some oxidized products.

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