Question

The vapour pressure of pure benzene at a certain temperature is 640 mm of hg and nonvolatile rutile solid waste 2.1 75 gram is added to 39 of benzene the vapour pressure of solution is 600 mm of hg what is molecular weight of solid substance

Answer 1

Answer:

I think answer is 157

Explanation:

vapour pressure is the normal pressure

Answer 2

Answer:69.6 g/ mol

Explanation:

According to Raoults law of lowering vapour pressure

delta P/P°=x2=n2/n1+n2

~ n2/n1

i.e P°-P solution /P°=W2/M2÷W1/M1

M2= W2.M2.P°/W1. (P°-Psol)

M2= 2.175×78×640/39×40

M2=69.6 /mol