The osmotic pressure of a solution of a synthetic polyisobutylene in benzene was determined at `25^(@)"C"`. A sample containing 0.20 g of solute/100`"cm"^(3)` of solution developed a rise of 2.4 mm at osmotic equilibrium. The density of the solution was` 0.88"g"//"cm"^(3)`. What is the molecular weight of the polyisobutylene?

Answer

`2.4xx10^(5)"g/mol"`

Explanation

`"h"_("Hg")=("h"_("sol.")xx"P"_("sol."))/("P"_("Hg"))=(2.4xx0.88)/(13.6)"mm of Hg"`
`pi=(2.4xx0.88)/(13.6xx760)"atm"`
`"m"_("B")=("W"_("B")"RT")/(pixx"V"_("sol")"(L)")`
`=(0.20xx0.082xx298)/((2.4xx0.88)/(13.6xx760)xx(100)/(1000))=2.4xx10^(5)"gm mol"^(-1)`