What is the osmotic pressure at 20°C of a solution made by dissolving 0.69 grams of sucrose, #C_12H_22O_11#, in 100 mL of water?
You need to quote the vapour pressure of water at
The vapour pressure of the SOLUTION, will be reduced proportional to the reduction of the concentration of WATER (i.e. the pure solvent) caused by dissolution of the sugar. Over to you.........