What is the expected osmotic pressure, in torr, of a 0.0100 M solution of NaCl in water at 25°C?
A) 186 torr
B) 0.245 torr
C) 372 torr
D) 15.6 torr
E) none of these

Question

Quizplus · Accepted Answer

The formula for calculating osmotic pressure (π) is π = MRTi, where M is the molar concentration, R is the gas constant, T is the temperature in Kelvin, and i is the van't Hoff factor. For NaCl, i = 2, since it dissociates into two ions (Na+ and Cl-).
Substituting the given values, we get:
π = (0.0100 M) x (0.08206 L atm mol^-1 K^-1) x (298 K) x (2)
π = 49.15 atm
Converting atm to torr, we get:
π = 49.15 atm x 760 torr/atm = 372 torr (rounded to three significant figures)

What Is the Expected Osmotic Pressure, in Torr, of a 0.0100