Osmotic pressure of 1 mol of idea solute relative to pure water is:

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.