Match the following if molecular masses of X, Y, Z are same

Explanation

`K_(b) = (RT_(b)^(2))/(1000 l_(vap))`
= `(RT_(b)^(2))/(1000 l_(vap)) = (RT_(b)M)/(1000 Delta S_(vap))`
`("because" (Delta H_(vap))/(T_(b)) = Delta S_(vap))`
The conversion of liquid to gas at the boiling point is accompanied by large increase in randomness. However, degree of randomness in vapours at their boiling point may be taken approximately constant, other factors being constant, we can use the approximation that `k_(b) prop T_(b)`. Thus.
`K_(b) (X) = 0.68 , K_(b) (Y) = 0.53 and K_(b) (Z) = 0.98` .