The correct relation for determining the molar mass of solute ($M_2$) using osmotic pressure measurement, is

$M_2=\frac{w_2RT}{ПV}$

The correct answer is Option (2) → $M_2=\frac{w_2RT}{ПV}$

Osmotic pressure is a colligative property that depends on the number of solute particles present in the solution. The fundamental relation for osmotic pressure is Π = CRT

where Π = osmotic pressure

C = molar concentration of solution

R = universal gas constant

T = absolute temperature

Molar concentration can be written as C = n / V

where n is the number of moles of solute and V is the volume of the solution.

Number of moles of solute is n = w₂ / M₂

where w₂ = mass of solute M₂ = molar mass of solute

Substituting in the osmotic pressure equation:

Π = (w₂ / M₂V) RT

Rearranging to obtain molar mass: M₂ = (w₂RT) / (ΠV)

Thus the correct relation for determining molar mass using osmotic pressure is M₂ = (w₂RT) / (ΠV)