Manipal MET2010ChemistrySolutions
The relative lowering of vapour pressure of a dilute aqueous solution containing non volatile solute is 0.0125 . The molality of the solution is about
Options
- A0.70
- B0.50
- C0.90
- D0.80
Correct answer
A. 0.70
Step-by-step solution
Relative lowering of vapour pressure = mole fraction of solute (Raoult's law) p-p_S p = ₂ p-p_S p = w M m W 0.0125= w M m W or w m W = 0.0125 18 =0.00070 Hence, molality = w m W 1000=0.0007 1000=0.70