$\begin{array}{1 1}170.7gmol^{-1}\\270.7gmol^{-1}\\370.7gmol^{-1}\\470.7gmol^{-1}\end{array} $

Let $M$ be the molar mass of phenol in ether.

We will have ,molality of solution =$\large\frac{2.0}{(100/1000)}$

Now using the expression $-\Delta T_f=K_fm$

We get,

$0.60K=(5.12Kkg mol^{-1})(\large\frac{20}{M}\frac{g}{kg})$

Which gives $M=\large\frac{5.12\times 20}{0.60}$$g mol^{-1}$

$\Rightarrow 170.7gmol^{-1}$

Since the calculated molar mass is about twice of its actual molar mass $(94gmol^{-1})$,it may be concluded that the phenol in ether is almost present in dimerized form

Ask Question

Tag:MathPhyChemBioOther

Take Test

...