KOLM Posted May 31 Share Posted May 31 Hi, Have some chromic acid and it is very damp as it is very hygroscopic. Does anyone know of a way to dry it out? Maybe over conc sulfuric acid or anhydrous calcium chloride? Could not find anything on the internet. Thanks. Link to comment Share on other sites More sharing options...
chenbeier Posted May 31 Share Posted May 31 For what reason you want to dry it. It's a very poisson and cancerogene stuff. Normally it will be dissolved in water or sulfuric acid as etching compound. Drying with Phosphorous pentoxide is possible. Link to comment Share on other sites More sharing options...
KOLM Posted June 1 Author Share Posted June 1 16 hours ago, chenbeier said: For what reason you want to dry it. It's a very poisson and cancerogene stuff. Normally it will be dissolved in water or sulfuric acid as etching compound. Drying with Phosphorous pentoxide is possible. Thanks, Chen. I need to dry it to avoid customers complaining about damp chromic acid. I guess I have nothing to loose from trying it, weigh up a small sample, the after a week reweigh. Might start with calcium (I dont have phos pentoxide handy, although a great choice. Link to comment Share on other sites More sharing options...
exchemist Posted June 1 Share Posted June 1 19 hours ago, KOLM said: Hi, Have some chromic acid and it is very damp as it is very hygroscopic. Does anyone know of a way to dry it out? Maybe over conc sulfuric acid or anhydrous calcium chloride? Could not find anything on the internet. Thanks. Are you referring to chromium trioxide? Link to comment Share on other sites More sharing options...
chenbeier Posted June 1 Share Posted June 1 (edited) 1 hour ago, exchemist said: Are you referring to chromium trioxide? Chromium-VI-trioxide CrO3 is called in publics mouth as chromic acid. If it get wet then it reacts to a sludge n CrO3 + H2O => H2(CrO3)(n-1)CrO4 With n= 2 for example it will be H2Cr2O7 Dichromic acid. Edited June 1 by chenbeier Link to comment Share on other sites More sharing options...
exchemist Posted June 1 Share Posted June 1 15 minutes ago, chenbeier said: Chromium-VI-trioxide CrO3 is called in publics mouth as chromic acid. If it get wet then it reacts to a sludge n CrO3 + H2O => H2(CrO3)(n-1)CrO4 With n= 2 for example it will be H2Cr2O7 Dichromic acid. OK thanks. Link to comment Share on other sites More sharing options...
KOLM Posted June 3 Author Share Posted June 3 On 6/1/2024 at 11:07 AM, chenbeier said: Chromium-VI-trioxide CrO3 is called in publics mouth as chromic acid. If it get wet then it reacts to a sludge n CrO3 + H2O => H2(CrO3)(n-1)CrO4 With n= 2 for example it will be H2Cr2O7 Dichromic acid. Wow, Chen, I didnt know. So, even if I were to dry it out some, it would not revert back to CrO3? Link to comment Share on other sites More sharing options...
chenbeier Posted June 3 Share Posted June 3 (edited) 6 minutes ago, KOLM said: Wow, Chen, I didnt know. So, even if I were to dry it out some, it would not revert back to CrO3? Correct, it's difficult to keep it dry after open the container. Edited June 3 by chenbeier Link to comment Share on other sites More sharing options...
KOLM Posted June 3 Author Share Posted June 3 2 hours ago, chenbeier said: Correct, it's difficult to keep it dry after open the container. Meaning, to clarify, once damp, it is not anymore CrO3, but a different compound H2Cr2O7 (?). Link to comment Share on other sites More sharing options...
chenbeier Posted June 3 Share Posted June 3 CrO3, H2CrO4, H2Cr2O7, etc. All are chromic acid. On 6/1/2024 at 4:04 PM, exchemist said: Are you referring to chromium trioxide? Link to comment Share on other sites More sharing options...
KOLM Posted June 4 Author Share Posted June 4 Thans again, Chen. That helps. Link to comment Share on other sites More sharing options...
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