At `STP5.6 "litre"` of a gas weigh `60 g`. The vapour density of gas is:

Answer

To find the vapor density of the gas given that at STP, 5.6 liters of the gas weighs 60 grams, we can follow these steps:

### Step 1: Understand the Concept of Vapor Density
Vapor density is defined as the ratio of the molar mass of the gas to the molar mass of hydrogen (H₂). The molar mass of hydrogen (H₂) is 2 g/mol (since the atomic mass of hydrogen is 1 g/mol).

### Step 2: Calculate the Molar Mass of the Gas
At STP (Standard Temperature and Pressure), 22.4 liters of any gas has a mass equal to its molar mass. We are given that 5.6 liters of the gas weighs 60 grams.

Using the unitary method, we can find the mass of 1 liter of the gas:
\[ \text{Mass of 1 liter} = \frac{60 \text{ g}}{5.6 \text{ L}} = \frac{60}{5.6} \approx 10.71 \text{ g/L} \]

Now, to find the mass of 22.4 liters:
\[ \text{Mass of 22.4 liters} = \left(\frac{60 \text{ g}}{5.6 \text{ L}}\right) \times 22.4 \text{ L} = 10.71 \text{ g/L} \times 22.4 \text{ L} \approx 240 \text{ g} \]

Thus, the molar mass of the gas is approximately 240 g/mol.

### Step 3: Calculate the Vapor Density
Now that we have the molar mass of the gas, we can calculate the vapor density:
\[ \text{Vapor Density} = \frac{\text{Molar Mass of Gas}}{\text{Molar Mass of H}_2} = \frac{240 \text{ g/mol}}{2 \text{ g/mol}} = 120 \]

### Final Answer
The vapor density of the gas is **120**.

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