Molecular weight of a gas, 11.2 litres of which at NTP weighs 14 g, is

Options

A. 14
B. 28
C. `14/(11.2)`
D. `14 xx 11.2`

Answer

To find the molecular weight of the gas, we can follow these steps:

### Step 1: Understand the conditions
At Normal Temperature and Pressure (NTP), 1 mole of any ideal gas occupies 22.4 liters.

### Step 2: Calculate the number of moles of the gas
We know that 11.2 liters of the gas weighs 14 grams. To find the number of moles, we can use the formula:

\[ \text{Number of moles} = \frac{\text{Volume of gas at NTP}}{\text{Volume occupied by 1 mole at NTP}} \]

Substituting the values:

\[ \text{Number of moles} = \frac{11.2 \, \text{liters}}{22.4 \, \text{liters/mole}} = 0.5 \, \text{moles} \]

### Step 3: Calculate the molecular weight
Molecular weight (or molar mass) can be calculated using the formula:

\[ \text{Molecular weight} = \frac{\text{Mass of gas}}{\text{Number of moles}} \]

Substituting the known values:

\[ \text{Molecular weight} = \frac{14 \, \text{g}}{0.5 \, \text{moles}} = 28 \, \text{g/mole} \]

### Conclusion
The molecular weight of the gas is **28 g/mol**.

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