When 9.12 g of HCl was dissolved in 190 g of water, the freezing point of the solution was -4.65^{o}C. What is the value of the van't Hoff factor for HCl?

Here is what I did-

I know that I use: deltaT= K_{f} x m x i

rearranged to solve for i: deltaT/K_{f} x m

solving for molality:

mol HCl=0.250

kg solvent= .190

m=0.250/.190= 1.32

i= -4.65^{o}C/1.86 x 1.32 = -1.89

I am not sure if the value for i can be negative or if I did the problem correctly. Please help me! Thanks!

## Comments

(delta)f{initial freezing-final freezing point as depression of freezing point occurs } =iKfM —> i = deltaf/KfM delta f = 0 - (-4.65) = +4.65 so i is +... actually we always take temperature in kelvin and freezing point of water is 272.15k and new freezing point is 267.50k.

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