[organosurf]

In the generation of HCl(g), 37%Conc HCl is added to 98%Conc H2SO4.
I find this strange, as Conc HCl is 37% ACID and 63% WATER whereas, Conc H2SO4 is 98% ACID and 2% WATER; meaning if the golden rule of adding ACID to WATER is followed, shouldn’t it be the other way around, ie. adding the substance containing MORE ACID ( 98%Conc H2SO4 ) to that substance containing MORE WATER ( 37%HCl)

PS. I have NO intention of finding this out experimentally ! 

 
   

[Arkcon]

The biggest risk of adding water to acid in an open beaker or regular flask is the water floating on top as its added to the denser liquid, boiling away, and splashing acid on the user.  If you've got a giant flask with a side arm, and a dropping funnel or thistle tube releasing HCl under the water surface, then you likely won't get a mess.  After all, you have to have some way of catching HCl vapor, and drying it, in order to use it.  So you're already trying to keep liquid under control.

[organosurf]

Thanks for your answer ! There is mention of releasing HCl(g) in the aforesaid manner; can the same principle or method be used to release HBr(g) from 48% Conc HBr ? Of course there will be some oxidation by 98% Conc H2SO4 of HBr(g) into Br2(l) ?

[Hunter2]

No, because mainly bromine will be optained. HBr is made by adding bromine to a carbonhydrogen like hexane or using PBr₃ with water. Also HCl I would produce with PCl₃ or using a gas bottle containing it.