Question

Choose the aqueous solution below with the highest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

(i) 0.200 m HOCH2CH2OH
(ii) 0.200 m Ba(NO3)2
(iii) 0.200 m K3PO3
(iv) 0.200 m Ca(CIO4)2
(v) These all have the same freezing point.

Answer 1

0.200 m K3PO3

Step-by-step explanation:

Let us remember that the freezing point depression is obtained from the formula;

ΔTf = Kf m i

Where;

Kf = freezing point constant

m = molality

i = Van't Hoff factor

The Van't Hoff factor has to do with the number of particles in solution. Let us consider the Van't Hoff factor for each specie.

0.200 m HOCH2CH2OH - 1

0.200 m Ba(NO3)2 - 3

0.200 m K3PO3 - 4

0.200 m Ca(CIO4)2 - 3

Hence, 0.200 m K3PO3 has the greatest van't Hoff factor and consequently the greatest freezing point depression.