It should remain constant because of the law of conservation of mass and because the flask is sealed no mass will escape
(P1)(V1)=(P2)(V2)
(1.50)(5.00)=(1240/760)(V2)
(7.5)/(1240/760)=V2
V2=4.596774194 L
I believe the correct answer from the choices listed above is option A. The topic that the teacher is talking about would be distillation of a mixture. Gasoline is processed by distillation. Hope this answers the question. Have a nice day.
HSDB and the SRC Physical Properties database database reports that propionic acid has a water solubility of 1000 g/l at 25 °C. Ullmann and Knovel Solvents - A Properties Database reports that propionic acid is miscible in any ratio with water.