Considering the mixture of two volatile liquids in a closed system, we derived t
ID: 931424 • Letter: C
Question
Considering the mixture of two volatile liquids in a closed system, we derived the following relationship between the chemical composition of the liquid phase (mole fraction x) and the composition of the vapor phase (mole fraction y): Show, mathematically, that in the case that one liquid is much, much more volatile than the other, this is consistent with the CHE222 prediction we make about a solution with a volatile solvent and a non-volatile solute: What does this simplify to, mathematically, in the case that one component in the solution is much, much more volatile than the other? What does this mean, chemically?Explanation / Answer
if one liquid is more volatile than the other,then p*B>p*A (B is more volatile than A), then (p*B-p*A)=positive
the total pressure=p=P*B+(p*B-p*A)Xa increases with increase of mole fraction Xa.
if (B is much more volatile than A then, the term (p*B-p*A)=p*B
yA=xA p*A/p*B(1-Xa)=xA p*A/p*B Xb where Xb=mole fraction of B
yA=pA/pB
yB=1-yA=1-pA/pB=pB-pA/pB=pB/pB=1...(so the vapour phase consist of vapours of component B only)
that means component A is non-volatile and does not form vapours