Physiology Osmotic pressure of 1 mol of ideal solute relative to pure water is: (PGI June 2009) A 6.5 atm. B 22.4 atm. C 4 atm. D 2 atm. 💡 Explanation Osmotic pressure of 1 mol of ideal solute relative to pure water is: (PGI June 2009) ✓ Correct Answer: B. 22.4 atm.