Desalination of seawater by reverse osmosis requires application of a pressure in excess of the solutions osmotic pressure.What is the osmotic pressure of a 5.0 g NaCl/L solution at 25 $\circ$ C? (assume the van't Hoff factor i = 2; R = 0.0826 L.atm/mol.K)

Question

Quizplus · Accepted Answer

The osmotic pressure (π) can be calculated using the formula π = iMRT. First, calculate the molarity (M) of the NaCl solution: M = (5.0 g/L) / (58.44 g/mol) = 0.0856 mol/L. Then, π = (2)(0.0856 mol/L)(0.0826 L·atm/mol·K)(298 K) = 4.2 atm.

Desalination of Seawater by Reverse Osmosis Requires Application of a Pressure