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# Calculate the osmotic pressure of 0.500 M sodium chloride at 25oC. A) 12.2 atm B) 1.03 atm C) 36.6 atm D) 0.474 atm?

### 1 Answer

- hcbiochemLv 74 years ago
The equation for osmotic pressure is

Pressure = M R T where M is the molarity of particles in the solution, R is the gas constant and T is the Kelvin temperature. Since NaCl ionizes completely into two ions, the molarity of ions in the solution is 1.00 M. So:

Pressure = 1.00 (0.08206 Latm/molK) 298K = 24.4 atm

I don't like any of your answer choices. This should be the correct answer. Now, if the solution was of glucose, or something else that didn't ionize, A would be the correct answer, but that is certainly not correct for the solution given in the question.