Question

0.5 g of a non-volatile solute is dissolved in 100 g of ethyl acetate at 200
C. The vapour pressure of the solution and pure ethyl acetate are72.0 torr and 72.8 torr, respectively200
C. Calculate the molecular mass of the solute?

Answer 1

Explanation:

We have,

P

A

0

P

A

0

−P

S

=x

A

let molar mass of solute = M

so, moles of solute =

M

5.8

=x

and moles of solvent=

76

100

=1.31

we get,

195

195−190

=

x+1.31

x

x=0.0344 moles

we have,

M

5.8

=0.034

thus molar mass of solute = 170.6