Which of the following will have the lowest freezing point?

Question

0.1M NaCl
0.1M BaCl2
0.1M AlCl3
all have the same freezing point

Answer 1

The freezing point lowering effect is related to the concentration of all the ions (or molecules) in the solution. Since the AlCl3 puts 4 ions in solution/molecule it would give the largest freezing point lowering.

Answer 2

Freezing point depression = Kf x molality x i

Since all of these would be put in the same solute, the Kf would be the same for all of them

Since all have the same concentration, they would have the same m (although you were given Molarity and the actual equation uses molality, moles solute/kg of solvent)

i = van't hoff factor: how many particles are in solution when the species dissolves

NaCl ----> Na^+1 + Cl^-1 so NaCl produces 2 particles in solution so i = 2

BaCl2 -----> Ba^+2 + 2Cl^-1 so BaCl2 produces 3 particles in solution

AlCl3 ---> Al^+3 + 3Cl^-1 so AlCl3 produces 4 particles in solution

Therefore since the i factor is larger for AlCl3, the freezing point depression value will also be a larger number so the freezing point is MORE depressed (lower)

Answer 3

0.1M NaCl since when it dissolves in water
it has the least amount of solutes, meaning
less bonding between the molecule and
water.

Answer 4

0.1 M AlCl3
Flying Dragon is correct.

NaCl would yield the highest.

Answer 5

1M BaC12

duh