Mixture of `O_2` and `H_2` is used as

Options

A. rocket fuel
B. welding torch
C. water gas
D. oxidising agent

Explanation

To answer the question about the uses of a mixture of oxygen (O₂) and hydrogen (H₂), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Mixture**: The mixture of oxygen and hydrogen is commonly referred to as "oxyhydrogen." This mixture consists of two gases: hydrogen (H₂) and oxygen (O₂).

2. **Applications of Oxyhydrogen**:
- **Welding**: One of the primary uses of the oxyhydrogen mixture is in welding. The high-temperature flame produced by burning hydrogen in oxygen is used for welding metals. This is known as an oxyhydrogen torch.
- **Refractory Processes**: The oxyhydrogen mixture is also used in processes involving refractory materials, which are materials that can withstand high temperatures without melting or deforming.

3. **Evaluate the Options**: Given the options:
- A) Rocket fuel
- B) Welding torch
- C) Water gas
- D) Oxidizing agent

The correct answer is **B) Welding torch**, as it directly relates to the application of the oxyhydrogen mixture in welding.

4. **Conclusion**: Therefore, the mixture of oxygen and hydrogen is primarily used as a welding torch and in refractory processes.