Sorry butcher it's the Fusion point i gave not boiling point. The fusion temperature of HAuCl4 is 30°C means that at 30°C.
The boiling point is 200°C in French wiki
http://fr.wikipedia.org/wiki/Acide_chloraurique
But the information given in the english wiki is diffrent :
http://en.wikipedia.org/wiki/Chloroauric_acid here they gave the melting point and it's 254°C.
Now what do we have in our standard solutions of gold that have been precipitated and syhoned, ready to be washed with HCl ?
we have: HAuCl4, very little H2O , very little HCl and let's say some of unwanted molecules such as : Urea Nitrate or just urea, and some other metals in traces.
Let's focus just on theese molecules / ions, considering the denoxing was perfectly done, we dont need to speak about azeotrope and so on...
So What we just want by washing is :
* to get rid of the reste of unwanted traces if other metals precitpitated with our gold or those who dident react previously.
* get rid of the urea excess or urea nitrates (that dident react to give gases :
(NH2)2 CO [urea] + HNO3 [nitric acid] ------> 3 NO + CO2 + H2O )
* AND MOST OF ALL now we want our pure gold chlorides molecules only to stay :
Au2Cl6 + HCl <---------> HAuCl4
in this last reaction we do have to care about all it's chemistry caracteristics
boiling point, fusion point, only this coz we consider our initial solution of AR was clean, the most clean we can.
Why i port my interest to this reaction is coz it's a complex reaction in reality
it depends on pH and Temperature (not pressure coz i consider working under atmospheric condition) and (may some gold is under AuCl form ? )
i want to try to explein this reaction in details if no one else have done this before, or knows how things goes considering this 2 parameters pH and Temperature.
Hope u understand me