andyloris - 22-10-2022 at 08:52
I tried disolving chromium(III) oxide in hydrochloric acid, however it didn't work and I was left with chromium(III) oxide stains in my flat bottom
flask.
How do I clean them ?
Thanks in advance !
andyloris - 29-10-2022 at 09:15
Guess my flask is gonna stay green forever ...
Bedlasky - 29-10-2022 at 09:27
I don't have experience with this issue, but when I needed clean something from Fe(OH)3, oxalic acid always worked very well. Try that. Or maybe
bleach will help - it oxidize Cr2O3 to water soluble chromate. If Cr2O3 is deposited as a thin layer on the glass, you can try 40% NaOH - it eat away
very small amount of glass and Cr2O3 won't stick to it anymore (and maybe even dissolve in NaOH).
clearly_not_atara - 29-10-2022 at 10:20
Could try forming the oxalate complex with refluxing potassium hydrogen oxalate?
andyloris - 29-10-2022 at 12:21
Thanks !
macckone - 31-10-2022 at 08:55
If hypochlorite does not work, there is always chlorate and bromate.
Depending on how tenacious the chromium oxide is, bromate may be the agent you need.