This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Osmotic pressure of 1 mol of idea solute relative to pure water is: 
Select and explain. 
A. 6.5 atm., B. 22.4 atm., C. 4 atm., D. 2 atm.
B: 22.4 atm.
Answer: B: 22.4 atm. 
Explanation: B i.e. 22.4 1 mol of an ideal solute dissolved in 1 kg (1000 gm) of water (i.e. 1 molal or M solution) at 1 atm pressure at 25degC yields a solution whose osmotic pressure relative to pure water is 22.4 atmQ.