which of the following would be expected to have the lowest freezing temperature?

a. .1 M Ca(NO3)2
b. .1 M NaC2H3O2
c. .1 M CuSO4
d. .1 M HC2H3O2
e. .1 M C2H5OH

Here is what you do Mary.
delta T = Kb*i*m
Kb is the same for all.
m is the same for all.
i is the number of particles in solution. I assume the solvent is water.
Ca(NO3)2 gives 3 particles when it ionizes. One Ca ion and 2 nitrate ions to make a total of 3.
Go through the group. The one with the largest i will be the one with the largest delta T and therefore the lowest freezing point.

so it's a right? because all of the others only yeild 2 particles when they ionize