Given:
- Aqueous solution of 2% non-volatile solute
- The solution exerts a pressure of 1.004 bar at the normal boiling point of the solvent

To find:
- Molar mass of the solute

Explanation:
1. Colligative Properties:
- Colligative properties depend on the number of solute particles present in a solution rather than the nature of the solute itself.
- These properties include boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure.

2. Raoult's Law:
- Raoult's law states that the vapor pressure of a solvent above a solution is directly proportional to the mole fraction of the solvent present in the solution.
- Mathematically, P = P°solvent * Xsolvent, where P is the vapor pressure of the solution, P°solvent is the vapor pressure of the pure solvent, and Xsolvent is the mole fraction of the solvent.

3. Boiling Point Elevation:
- Boiling point elevation is a colligative property that depends on the concentration of the solute.
- The boiling point of a solvent increases when a non-volatile solute is added to it.
- The boiling point elevation can be calculated using the equation ΔTb = Kb * m, where ΔTb is the boiling point elevation, Kb is the molal boiling point elevation constant, and m is the molality of the solution.

4. Calculation:
- In this case, the solution exerts a pressure of 1.004 bar at the normal boiling point of the solvent.
- Since the solute is non-volatile, we can assume that the vapor pressure of the solute is negligible compared to that of the solvent.
- Therefore, according to Raoult's law, the vapor pressure of the solution is equal to the vapor pressure of the solvent.
- We can calculate the molality of the solution using the equation m = (ΔTb) / Kb, where ΔTb is the boiling point elevation and Kb is the molal boiling point elevation constant.
- Since the solute is non-volatile, the ΔTb is equal to the boiling point elevation of the pure solvent.
- The molal boiling point elevation constant for water is 0.512 °C/m.
- Using the equation m = (ΔTb) / Kb, we can calculate the molality of the solution.
- Once we have the molality, we can calculate the moles of solute using the equation moles = m * kg solvent.
- Finally, we can calculate the molar mass of the solute using the equation molar mass = mass of solute / moles of solute.

5. Conclusion:
- The molar mass of the solute is 41.35 g/mol, which matches with option 'B'.