# Given that the freezing point depression constant for water is 1.86 C kg/mol, how do you calculate the change in freezing point for a 0.833m sugar solution?

Jul 16, 2018

Is not freezing point depression simply the product....

#### Explanation:

$\text{Freezing point depression"=k_fxx"molality of solution}$

...where ${k}_{f} = {\underbrace{1.86 \cdot K \cdot k g \cdot m o {l}^{-} 1}}_{\text{molal freezing point depression constant}}$

And so the observed molal freezing point depression is...

$1.86 \cdot K \cdot k g \cdot m o {l}^{-} 1 \times 0.833 \cdot m o l \cdot k {g}^{-} 1 = + 1.55 \cdot K$..

But this is a freezing point depression, and so the fusion point of the solution should be $- 1.55$ ""^@C...

How would the freezing point evolve if we had a solute that underwent speciation in aqueous solution, i.e. say sodium acetate or sodium chloride?