Chemistry question: chemical formula for freezing water with a solute?

[FeralisExtremum]

What would the expression be for freezing water mixed with some solute (e.g. saltwater)? For example, dissolving salt in water goes by:

H2O (l) + NaCl (s) --> H2O (l) + Na+ (aq) + Cl- (aq)

Now let's say I wanted to show the reaction of the saltwater mixture freezing - I know that it would go from H2O (l) --> H2O (s), but what happens with the salt? Is it sill considered aqueous and separated?

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[tandem7]

I'm pretty sure that Na+ and Cl- are still in their ionic form and therefore can only be aqueous. In that case, if water freezes (clearly at a lower temperature if salt was in it), then the Na+ and Cl- ions would be suspended in the water's crystals but would not be frozen itself. It can only be in solid form if it were in its own ionic lattice as NaCl(s).

 

[Ari Rezaei]

Pretty detailed question, but if the solution gets cold enough to freeze the salt would precipitate out and turn into NaCl(s), just would have to get colder than usual due to the NaCl. The hardest question you'll be asked about this would be related to freezing point depression.