# At 35$^{\large\circ}$C the vapour pressure of $CS_2$ is 512 mm Hg, and of acetone, $CH_3COCH_3$, is 344 mm Hg. A solution of $CS_2$ and acetone in which the mole fraction of $CS_2$ is 0.25 has a total vapour pressure of 600 mm Hg. Which of the following statements about solution of acetone $-CS_2$ is true?

When acetone and $CS_2$ are mixed at 25$^{\large\circ}$C, heat must be absorbed in order to produce a solution at 35$^{\large\circ}$C