The vapour density of an element is 14. Calculate is molecular mass.

Options

A. 14
B. 7
C. 28
D. Infinite

Explanation

To calculate the molecular mass of an element given its vapor density, we can follow these steps:

### Step 1: Understand the relationship between vapor density and molecular mass
Vapor density (VD) is defined as the mass of a certain volume of the gas compared to the mass of an equal volume of hydrogen at the same temperature and pressure. The formula for vapor density is:

\[ \text{Vapor Density} = \frac{\text{Molecular Mass}}{2} \]

This means that the molecular mass of the gas can be calculated by rearranging the formula:

\[ \text{Molecular Mass} = 2 \times \text{Vapor Density} \]

### Step 2: Substitute the given vapor density into the formula
The problem states that the vapor density of the element is 14. We can substitute this value into the formula we derived:

\[ \text{Molecular Mass} = 2 \times 14 \]

### Step 3: Perform the calculation
Now, we calculate the molecular mass:

\[ \text{Molecular Mass} = 2 \times 14 = 28 \]

### Step 4: State the final answer
Thus, the molecular mass of the element is 28 g/mol.