`5*6` L of a gas at S.T.P. weights equal to 8 g. The vapour density of gas is

Options

A. 32
B. 16
C. 8
D. 40

Explanation

To find the vapor density of the gas, we can follow these steps:

### Step 1: Understand the relationship between volume, mass, and molar mass.
At standard temperature and pressure (STP), 1 mole of any gas occupies 22.4 liters. We are given that 5.6 liters of the gas weighs 8 grams.

### Step 2: Calculate the number of moles of the gas.
Using the volume of the gas at STP, we can find the number of moles (n) of the gas using the formula:
\[ n = \frac{\text{Volume of gas}}{22.4 \, \text{L/mol}} \]
Substituting the values:
\[ n = \frac{5.6 \, \text{L}}{22.4 \, \text{L/mol}} = 0.25 \, \text{mol} \]

### Step 3: Calculate the molar mass of the gas.
Molar mass (M) can be calculated using the formula:
\[ M = \frac{\text{Mass of gas}}{\text{Number of moles}} \]
Substituting the values:
\[ M = \frac{8 \, \text{g}}{0.25 \, \text{mol}} = 32 \, \text{g/mol} \]

### Step 4: Calculate the vapor density of the gas.
Vapor density (VD) is defined as half of the molar mass of the gas:
\[ VD = \frac{M}{2} \]
Substituting the molar mass we calculated:
\[ VD = \frac{32 \, \text{g/mol}}{2} = 16 \, \text{g/L} \]

### Final Answer:
The vapor density of the gas is **16 g/L**.

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