QUESTION $2$

Three gram$-$moles of benzene and seven gram$-$moles of toluene are placed in a closed cylinder equipped with a piston. The cylinder is immersed in a bath of boiling water that maintains the temperature at $100C.$ The force exerted on the piston can be varied to adjust the cylinder pressure to any desired value. The pressure is initially $1000mmHg$ and is gradually lowered to $600mmHg.$ Assume that the cylinder initially contains only liquid benzene and toluene, use the Pxy diagram to answer the following questions:

$($a$)$ At what pressure does the first vapor bubble form? What is its composition? $($Answer: $P=798+-1mmHg,($:$y_B=0\mathrm{.}50+-0\mathrm{.}01(mol)(B)\frac{v}{m}ol$