Sciencemadness Discussion Board

Aqua regia effects of formation

chornedsnorkack - 13-9-2024 at 04:33

There is a maxim, often stated as general rule, to "add acid to water, not water to acid".
There is some reasoning underneath it when the acid is concentrated sulphuric acid. (Large release of heat of solution, boiling water would float).
What are the heats of mixing for aqua regia?
Is there any rule as to whether nitric acid should be added to hydrochloric acid or hydrochloric acid to nitric acid?
Apart from temperature, what does mixing of aqua regia do to vapour pressures of components? Can mixing of acids that are previously short of saturation bring about saturation relative to either existing solutes (HCl, NO2) or the reaction products (NOCl, Cl2)?

DraconicAcid - 13-9-2024 at 18:35

Nitric and hydrochloric are similar viscosities. You can mix them in whichever order.