<u>Answer:</u> The molar mass of unknown solute is 195.44 g/mol.
<u>Explanation:</u>
To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

where,
= osmotic pressure of the solution = 0.750 atm
i = Van't hoff factor = 1 (for non-electrolytes)
c = concentration of solute = ?
R = Gas constant = 
T = temperature of the solution = ![25^oC=[273+25]=298K](https://tex.z-dn.net/?f=25%5EoC%3D%5B273%2B25%5D%3D298K)
Putting values in above equation, we get:

The concentration of solute is 0.0307 mol/L
This means that, 0.0307 moles are present in 1 L of solution.
To calculate the molecular mass of solute, we use the equation:

Moles of solute = 0.0307 mol
Given mass of solute = 6g
Putting values in above equation, we get:

Hence, the molar mass of unknown solute is 195.44 g/mol.