`100 cm^3` of a centimolar solution of an acid contain 0.098 g of the acid. Find the molecular mass of the acid.

Answer

To find the molecular mass of the acid from the given information, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concentration**:
A centimolar solution means that there are 0.01 moles of solute (the acid) in 1 liter (1000 cm³) of solution.

2. **Calculate Moles in 100 cm³**:
Since we have 100 cm³ of the solution, we can calculate the number of moles of the acid in this volume.
\[ \text{Number of moles} = \text{Concentration (in moles per liter)} \times \text{Volume (in liters)} \]
\[ \text{Number of moles} = 0.01 \, \text{moles/liter} \times \frac{100 \, \text{cm}^3}{1000 \, \text{cm}^3} = 0.001 \, \text{moles} \]

3. **Given Mass of the Acid**:
The mass of the acid is given as 0.098 grams.

4. **Calculate Molecular Mass**:
The molecular mass can be calculated using the formula:
\[ \text{Molecular Mass} = \frac{\text{Mass}}{\text{Number of Moles}} \]
Substituting the known values:
\[ \text{Molecular Mass} = \frac{0.098 \, \text{g}}{0.001 \, \text{moles}} = 98 \, \text{g/mol} \]

5. **Conclusion**:
The molecular mass of the acid is 98 g/mol.