Which of the following represents a double base propellant ?

Options

A. Nitromethane
B. Nitrocellulose `+` nitroglycerine
C. `N_(2)O_(4)+` monomethylhydrazine
D. Liquid `H_(2)+`liquide `O_(2)`

Answer

To determine which option represents a double base propellant, we need to understand what a double base propellant is. A double base propellant consists of two main components: nitrocellulose and nitroglycerin.

### Step-by-Step Solution:

1. **Understand the Definition of Double Base Propellant**:
- A double base propellant is a type of propellant that contains both nitrocellulose and nitroglycerin.

2. **Identify the Components of One Base Propellant**:
- A one base propellant only contains nitrocellulose and does not include nitroglycerin.

3. **Analyze the Given Options**:
- **Option A**: Nitromethane - This is not a double base propellant.
- **Option B**: Nitrocellulose + Nitroglycerin - This is the correct representation of a double base propellant.
- **Option C**: N2O4 and Monomethylhydrazine - This is not a double base propellant.
- **Option D**: Liquid H2 and Liquid O2 - This is also not a double base propellant.

4. **Select the Correct Answer**:
- Based on the analysis, the correct answer is **Option B: Nitrocellulose + Nitroglycerin**.

### Final Answer:
The correct representation of a double base propellant is **Option B: Nitrocellulose + Nitroglycerin**.