Question

Calculate the vapour pressure lowering

caused by the addition of 68.4 g of

sucrose(molecular weight=342g) to 500 g

of water if the vapour pressure of pure

water at 25⁰c is 20.0 mm of hg​

Answer 1

Explanation:

According to Raoult's law,

P0P0−Ps=n+Nn

or △p=n+Nn.p0

Given: n=34250=0.146;N=18500=27.78 and P0=23.8

Substituting the value in the above equation,

△p=0.146+27.780.146×23.8=0.124 mmHg