In the Ostwald-Walker dynamic method for measuring relative lowering of vapour pressure, the loss in — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

In the Ostwald-Walker method, air first passes through the solution (picking up moisture $\propto P_s$), then through the pure solvent (picking up the remaining moisture up to its capacity $\propto P^0$). The extra moisture picked up from the solvent bulbs is directly proportional to $P^0 - P_s$.