The vapor pressure of water at 20 C is 17.5mmHg. What is the vapor pressure of water over a solution prepared from 200g of sucrose (#C_12H_22O_11#) and 112.3 g of water?
Note that by definition,
Because sucrose is involatile, the vapour pressure of the solution is proportional to the mole fraction of water:
We might have got better results if we used ethyl alcohol or acetone as the solvent rather than water, given that these organic solvents would have expressed a REDUCED mole fraction with respect to water, and thus a GREATER diminution in vapour pressure with respect to that of the pure solvent....