The process `C_7H_16 underset(670K) overset(Pt)(to) C_6H_5CH_3 + 4H_2` is a

Options

A. cracking process
B. reforming process
C. platforming process
D. substitution process.

Answer

To determine the type of chemical process represented by the reaction \( C_7H_{16} \) (heptane) converting to \( C_6H_5CH_3 \) (toluene) and \( 4H_2 \) in the presence of platinum at 670 K, we need to analyze the definitions of the processes mentioned.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- The reactant is \( C_7H_{16} \) (heptane).
- The products are \( C_6H_5CH_3 \) (toluene) and \( 4H_2 \) (hydrogen gas).

2. **Understand the Nature of the Reaction**:
- The reaction involves the conversion of a saturated hydrocarbon (heptane) into an aromatic hydrocarbon (toluene). This indicates a significant change in the molecular structure.

3. **Define the Processes**:
- **Cracking Process**: This involves breaking down larger hydrocarbons into smaller ones, usually under heat and pressure.
- **Reforming Process**: This involves rearranging the molecular structure of hydrocarbons to change their properties.
- **Platforming Process**: This is a specific type of reforming that converts aliphatic hydrocarbons into aromatic hydrocarbons in the presence of a catalyst (like platinum) and often releases hydrogen gas.
- **Substitution Process**: This involves replacing one element in a compound with another.

4. **Analyze the Reaction**:
- The reaction converts a straight-chain alkane (heptane) into an aromatic compound (toluene), which indicates a rearrangement of the molecular structure.
- The presence of platinum as a catalyst and the release of hydrogen gas further suggests that this is not just a general reforming process but specifically a platforming process.

5. **Conclusion**:
- Since the reaction involves the conversion of an aliphatic hydrocarbon to an aromatic hydrocarbon in the presence of a platinum catalyst and produces hydrogen gas, it is classified as a **platforming process**.

### Final Answer:
The process \( C_7H_{16} \) (heptane) converting to \( C_6H_5CH_3 \) (toluene) and \( 4H_2 \) is a **platforming process**.