Answer: 1.0 M Al Cl3
Step-by-step explanation:
The vapor pressure is the pressure exerted by the molecules of vapor over a liquid.
The vapor pressure lowering is a colligative property.
A colligative property is a physical property of the solutions that depends on the number of particles of solute dissolved.
The greater the number of particles of solute dissolved the lower the resultant vapor pressure.
The ionic compounds dissociate into ions in water. To count for the dissociation of the ionic compounds it is used the van't Hoff factor (i). The higher the dissociation of the compounds, the higher the van't Hoff factor (i).
In ideal conditions, among the 4 solutes shown, AlCl3 has the highest van't Hoff factor, which means that the solution with 1.0 M AlCl3 will exhibit the lowest vapor pressure.
Answer: 1.0 M AlCl3