Question

The vapour pressure of pure benzene at certain temp is 262 bar. At the same temp the vapour pressure of solution containing 2g of non volatile solute is 100 g of benzene is 256 bar .What is molecular mass of solid?

Answer 1

Answer:

Psysaghi31Virtuoso

pi° =0.850 bar:

p=0.845 bar:

M1 = 78 g mol-1

w2 = 0.5 g

w1=39g

Substituting these values In equation .

and calculating,

M2= 170 g mol-1 3 years ago

P°=0.850

P'=0.845

No of moles of benzene=39/78=0.5

No of moles of solute=x

(P°-P')/p°=mole fraction of solute

P°-p'=0.005

Mole fraction of solute=0.005/0.850----*1

Mole fraction of solute=x/(x+0.5)-----*2

Sub eq 1 and 2

X=169g