If the vapour density of a gas is 15, its relative molecular mass will be _________

Options

A. 30
B. 7.5
C. zero
D. can't be determined

Explanation

To find the relative molecular mass of a gas given its vapor density, we can use the formula:

**Relative Molecular Mass (RMM) = 2 × Vapor Density (VD)**

### Step-by-step solution:

1. **Identify the given information**:
- The vapor density (VD) of the gas is given as 15.

2. **Use the formula to calculate RMM**:
- We will substitute the value of vapor density into the formula:
\[ RMM = 2 \times VD \]
- Substituting the value:
\[ RMM = 2 \times 15 \]

3. **Perform the multiplication**:
- Calculate the result:
\[ RMM = 30 \]

4. **Conclusion**:
- The relative molecular mass of the gas is 30.

### Final Answer:
The relative molecular mass will be **30**.

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