Question

At equal concentrations, would a nonelectrolyte (e.g. glucose) or electrolyte (e.g.NaCl) containing solution have a lower freezing point? Why?

Answer 1

Solution with electrolyte will have a lower freezing point than the solution with non electrolyte.

Step-by-step explanation:

Depression in freezing point is given by :

`\Delta T_f=i* k_f* m`

Where :

i = van't Hoff factor

`k_f` = Molal depression constant of solvent

m = molaity of the solution

Let the molality of the glucose and NaCl solution be = m

Molal depression constant of water =
`k_f`

1) The values of van't Hoff factor for glucose is = 1 (non electrolyte)

Depression in freezing point of glucose solution :

`\Delta T_f=1* k_b\time m`

2) The values of van't Hoff factor for NaCl is = 2 (electrolyte)

`NaCl\rightarrow Na^++Cl^-`

Depression in freezing point of NaCl solution :

`\Delta T_f'=2* k_b\time m`

`\Delta T_f<\Delta T_f'`

`1* k_b\time m<2* k_b\time m`

1 < 2

Higher the depression in freezing point more will be the lower freezing point of the solution.This means that solution with electrolyte will have a lower freezing point than the solution with non electrolyte.