Which one of following is a cracking process ?

Options

A. `C_3 H_6 +H_2 rarr C_3 H_8`
B. `nC_2 H_4 rarr (C_2 H_4)_n`
C. `C_6H_(34) rarr 6CH_4 + 2 C_2 H_4 + C_2 H_2 + 4 C`
D. ` 3 C_2 H-2 rarr C-6 H_6`

Answer

To determine which of the following is a cracking process, we first need to understand what cracking is. Cracking is a chemical process that involves breaking down large hydrocarbon molecules into smaller, more useful molecules. This is commonly done in the petrochemical industry to convert crude oil into gasoline and other products.

### Step-by-Step Solution:

1. **Understand the Definition of Cracking**:
- Cracking refers to the process of breaking down large hydrocarbon molecules into smaller ones. This is typically done to convert heavy oils into lighter, more valuable products.

2. **Identify the Options**:
- We need to evaluate the provided options to see which one involves the splitting of large molecules into smaller ones.

3. **Analyze Each Option**:
- **Option A**: This option does not involve the splitting of large molecules into smaller ones. Therefore, it is not a cracking process.
- **Option B**: This option describes the formation of a larger molecule from smaller ones, which is the opposite of cracking. Hence, it is not a cracking process.
- **Option C**: This option shows a large molecule being split into smaller molecules (e.g., methane, ethane, ethyne). This is characteristic of a cracking process.
- **Option D**: Similar to option B, this option involves creating a larger molecule from smaller ones, which is not a cracking process.

4. **Conclusion**:
- After analyzing all the options, we find that **Option C** is the only one that describes a cracking process, as it involves the breakdown of a large hydrocarbon into smaller fragments.

### Final Answer:
The correct answer is **Option C**.