Increasing vapor pressure??????

Question

Rank these water solutions in order of increasing vapor pressure:

Distilled water

1 m AlCl3 in water

1 m methanol in water

1 m CaCl2 in water

1 m KCl in water

Answer 1

the moles of species in solution will decrease vapor pressure

1 m AlCl3 in water releases 4 moles

1 m methanol in water has 1 mole

1 m CaCl2 in water releases 3 moles

1 m KCl in water releases 2 moles

lowest vapor pressure 1 M AlCl3

higher VP 1 M CaCl2

even higher Vap Press 1M KCl

higher vap press 1 m methanol in water

highest vap pressure Distilled water

these are the answers I think that they are looking for.

I think that they are looking for the vapor press ure of water affected by moles of solutes.

in real life one considers not just the # of moles affecting the vapor pressure of water, but also the contribution to the total pressure vapor pressure made by the solute. and mole for mole the solute methanol adds more pressure to the total than water loses.

the one with the actual greatest pressure is methanol & water.

but if you have not covered Raoult's law,... then they are not looking for it