SAM4CH - 12-3-2006 at 03:55
Can I precipitate NaCl, NaNO3 from a diluted solution using an organic solvent like Alcohol or acetone.
Note: I added few milliliters of ethanol to 60% perchloric acid which contains NaCl, and NaNO3 and I noticed white precipitate!! Is it inorganic
salts!?
If it is possible please what about solubility of those salts in alcohol and others organic solvents.
[Edited on 12-3-2006 by SAM4CH]
Nicodem - 12-3-2006 at 08:06
If it does not form a biphasic system then yes, usually the solubility of inorganic salts decreases in water/organic solvent mixtures. However,
acetone generally doesn’t work as it will rather tend to form two phases with water solutions of salts instead of precipitating anything.
Isopropanol also does that quite often and ethanol only rarely and with very concentrated solutions only.
According to pKa rules and the ionic character of the salts you can not have an aqueous solution of “60% perchloric acid which contains NaCl, and
NaNO3” literally as such. You will have an equilibrium which will be mainly undissociated HCl and HNO3 (and NO2+ etc.), sodium cations, perchlorate
anions, all in approximately 60% perchloric acid. This is usually not important, but in this case it is since consequently, by precipitation with
ethanol, you could only get NaClO4. The HCl and HNO3 might also esterify with ethanol to great extent in such a concentrated HClO4. But if your aim is
to purify HClO4 from the inorganic salts then beware: boiling off the ethanol from HClO4 would probably result in an explosion!