barren aqua regia solution

[arthur kierski]

i used an ar solution to eliminate any impurities from rh powder--- the solution became redish,but stanous test indicated no precious metals-----to this solution i added naoh and a white powder formed----
question:which hidroxide is white?----example ,iron hydroxide is deep brown,rh hidroxide is golden yellow
thanks for any tips
Arthur

ps: i heated rh powder in ar for one hour and then filtrated the pure rh powder out---- to the fitrate i added naoh and formed a white hydroxide

 

[butcher]

Table salt (NaCl) is white.
HCl + NaOH --> NaCl + H2O
From the reaction above we have table salt (NaCl is normally soluble in water unless the solution is very concentrated), notice the NaCl salt here is a chloride and not a hydroxide, your white salt could be a sulfate (if sulfuric acid was previously used) or a chloride, or even a hydroxide, and can be any metal that may have been in solution.

How concentrated was the solution?
Will it dissolve in water?
In dilute HCl?

Actually many metals can form white salts, and most hydroxides are insoluble, you can find articles of qualitative analysis, this can give you a way to test the salt to see what it is.

 

[arthur kierski]

Thanks Butcher,for your quick reply------as the ar solution was redish,i added naoh in the expectation of making some yellow rh hydroxide, which might have (rh powder) gone in the ar solution-----i was surprised when the naoh formed a white stuff-----
i asked the question just for curiosity----since i knew that there was no pms in the ar solution------sometimes this ar purification of rh powder ,depending on the source of the material,gives gold in the ar solution----
thanks again

Arthur

 

[butcher]

check this out, there are other like this one.
http://www.wiredchemist.com/chemistry/instructional/laboratory-tutorials/qualitative-analysis