PASSAGE-III : In chemistry, 'mole' is an essential tool for the chemical calculations. It is a basic SI unit adopted by the `14^(th)` general conference on weights and measurements in 1971. A mole contains as many elementary particles as the number of atoms present in 12 g of `""^(12)C`. 1 mole of a gas at STP occupies 22.4 litre volume. Molar volume of solids and liquids is not definite. Molar mass of a substance is also called gram-atomic mass or gram molar mass. The virtual meaning of mole is plenty, heap or the collection of large numbers. 1 mole of a substance contains `6.023xx10^(23)` elementary particles like atom or molecule. Atomic mass unit (amu) is the unit of atomic mass, e.g., atomic mass of single carbon is 12 amu.
5.6 litre of a gas at STP is found to have a mass of 22 g. The molecular mass of the gas is

Options

A. 22
B. 44
C. 88
D. 33

Explanation

To find the molecular mass of the gas given that 5.6 liters of it at STP has a mass of 22 grams, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the conditions at STP**:
At Standard Temperature and Pressure (STP), 1 mole of any gas occupies 22.4 liters.

2. **Calculate the number of moles in 5.6 liters**:
\[ \text{Number of moles} = \frac{\text{Volume of gas}}{\text{Molar volume at STP}} = \frac{5.6 \, \text{liters}}{22.4 \, \text{liters/mole}} = 0.25 \, \text{moles} \]

3. **Use the relationship between mass, moles, and molar mass**:
The formula relating mass, number of moles, and molar mass is:
\[ \text{Mass} = \text{Number of moles} \times \text{Molar mass} \]
Rearranging this gives:
\[ \text{Molar mass} = \frac{\text{Mass}}{\text{Number of moles}} \]

4. **Substitute the known values**:
We know the mass of the gas is 22 grams and the number of moles is 0.25 moles:
\[ \text{Molar mass} = \frac{22 \, \text{g}}{0.25 \, \text{moles}} = 88 \, \text{g/mole} \]

5. **Final answer**:
The molecular mass of the gas is **88 g/mol**.