An ideal solution containing 92.1 g of glycerin, C3H5(OH)3, and 184.4 g of ethanol, C2H5OH, is at 40°C. The vapor pressure of pure ethanol is 0.178 atm at 40°C. Glycerin is essentially nonvolatile at this temperature. Compute the vapor pressure and weight percentage of Glycerin.

The vapor pressure of the solution is 0.142 atm.

The weight percentage of Glycerin is 33.31%.

Explanation:

Vapor pressure of pure ethanol = p = 0.178 atm

Vapor pressure of the glycerin solution =

Mass of glycerin = 92.1 g

Moles of glycerin =

Mass of ethanol = 184.4 g

Moles of ethanol =

Relative lowering in the vapor pressure of the solution with non volatile solute  is equal to the mole fraction of solute.

The vapor pressure of the solution is 0.142 atm.

Weight percentage of glycerin is :

The weight percentage of Glycerin is 33.31%.