At 363 K , the vapour pressure of A is 21 kPa and that of B is 18 kPa . One mole of A and 2 moles of B are mixed. Assuming that this solution is ideal, the vapour pressure of the mixture is___________ kPa . ( Round of to the Nearest Integer ) .

Step-by-step solution

Given P A 0 = 21   kPa    ⇒ P B 0 = 18   kPa → An Ideal solution is prepared by mixing 1 mole A and 2 mole B . → X A = 1 3 and X B = 2 3 → According to Raoult's law P T = X A P A 0 + X B P B 0 ⇒    P T = 1 3 × 21 + 2 3 × 18 ⇒    P T = 7 + 12 = 19   kPa