`116 mg` of a compound on vaporisation in a Victor `-` Meyer's apparatus displaced `44.8 mL` of air measured at `S.T.P.` The molecular mass of the compound is

Options

A. 58 g/mol
B. 0.48 g/mol
C. 116g/mol
D. 44.8 g/mol

Answer

To find the molecular mass of the compound using the data provided, we can follow these steps:

### Step 1: Convert the mass of the compound from milligrams to grams.
Given:
- Mass of the compound = 116 mg

To convert milligrams to grams:
\[ \text{Mass in grams} = 116 \, \text{mg} \times 10^{-3} \, \text{g/mg} = 0.116 \, \text{g} \]

### Step 2: Use the volume of air displaced to find the number of moles of vaporized compound.
At standard temperature and pressure (STP), 1 mole of any gas occupies 22.4 L (or 22400 mL).

Given:
- Volume of air displaced = 44.8 mL

To find the number of moles of the gas:
\[ \text{Number of moles} = \frac{\text{Volume of gas}}{22.4 \, \text{L}} = \frac{44.8 \, \text{mL}}{22400 \, \text{mL}} = \frac{44.8}{22400} \, \text{mol} = 0.002 \, \text{mol} \]

### Step 3: Calculate the molecular mass of the compound.
The molecular mass (M) can be calculated using the formula:
\[ M = \frac{\text{mass of the substance}}{\text{number of moles}} \]
Substituting the values:
\[ M = \frac{0.116 \, \text{g}}{0.002 \, \text{mol}} = 58 \, \text{g/mol} \]

### Final Answer:
The molecular mass of the compound is **58 g/mol**.

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