Chemistry - Liquid Solution Question with Solution | TestHub

Molar mass of ${\mathrm{CH}}_2{\mathrm{Cl}}_2=12\times 1+1\times 2+35.5\times 2=85\mathrm{g}{\mathrm{mol}}^{-1}$ Molar mass of ${\mathrm{CHCl}}_3=12\times 1+1\times 1+35.5\times 3=119.5\mathrm{g}{\mathrm{mol}}^{-1}$ Moles of ${\mathrm{CH}}_2{\mathrm{Cl}}_2=40\mathrm{g}/85\mathrm{g}{\mathrm{mol}}^{-1}=0.47\mathrm{mol}$ Moles of ${\mathrm{CHCl}}_3=25.5\mathrm{g}/119.5\mathrm{g}{\mathrm{mol}}^{-1}=0.213\mathrm{mol}$ Total number of moles $=0.47+0.213=0.683\mathrm{mol}$ Mole fraction of component 2 $$=0.47\mathrm{mol}/0.683\mathrm{mol}=0.688$$ Mole fraction of component 1 $$=1.00-0.688=0.312$$ We know that: $$\begin{array}{rl}& {\mathrm{P}}_{\mathrm{T}}={\mathrm{p}}_1^0+\left({\mathrm{p}}_2^0-{\mathrm{p}}_1^0\right){\mathrm{x}}_2\\ & =200+(415-200)\times 0.688\\ & =200+147.9\\ & =347.9\mathrm{mm}\mathrm{Hg}\end{array}$$