Solubility of Sodium nitrate and nitrite

[Tas_T]

Hi, I wonder if anyone can share some info in regards to the reliability of the data that's available on the internet about the solubility of NaNO3 and NaNO2.
Everything I've found so far seems to point towards the nitrate being slightly more soluble than the nitrite and yet, when trying to separate a mixture of the two it looks like the nitrate is always the first to crystalize out .
Yes , I have been tested the crystals after every crystallization and most definitely the nitrate is crushing out while the concentration of the nitrite in the mother liquor is increasing after each crystallization.
I'm a bit confused. If anyone could help would much appreciate it .

 

[Borek]

Solubilities listed are for solutions containing a single compound, not a mixture, plus these are very highly concentrated solutions, with very high ionic strengths, so it is quite unlikely they will follow simple "linear" models.

As a rule of thumb - if the amount of dissolved substance is comparable with the amount of solvent (as in: not orders of magnitude lower) things are almost guaranteed to go awry.

 

[Tas_T]

Thanks for the reply.
So, could it be that if the compounds have similar solubility the one with higher concentration is likely to stay in solution ? I mean at least to a point ?
Gotta test that thought . . .

 

[Borek]

So, could it be that if the compounds have similar solubility the one with higher concentration is likely to stay in solution ? I mean at least to a point ?

"Likely" is too strong a word, more like "anything can happen" (definitely including the case where the higher solubility compound doesn't crash out first).