Calculate the vapour pressure of a solution containing 9g of glucose in 162g of water at 293K. The vapour pressure of water of 293K is 17.535mm Hg.

Explanation

For a solution of volatile liquids : .The partial vapour pressure of each component of the solution is directly. proportional to its móle fraction present in solution:
For a solution of non-volatile solute : The relative lowering of vapour pressure of dilute solution containing a non-volatile solute is equal to the mole fraction of solute.
Problem:
Wt of glucose ` (omega )` = 9 gms, Wt of water (W) = 162 gms
mole . wt of gulucose (m) = 180 , mole. wt of water (M) = 18 vapour pressure of water ` (rho^(@)) = 17.535` mm. Hg.
Formula : ` ( p^(0) - p)/( p^(0)) = ( omega M)/( m W) `
` ( 17 . 535 - p)/( 17 . 535) = (9 xx 18)/( 180 xx 162) ` ( or)
` 17.535 - p = (cancel(9) xx cancel (18) xx 1 . 7535)/( 180 xx cancel(162) _(cancel(18)))= (1.7535)/(18) = 0.0974 `
` :. p = 17.535 - 0.0974 = 7 . 4376 ` m m. Hg