To my knowledge, sulphuric acid is produced by complex industrial processes like contact process.
The following structure shows a sulphate ion.
I wonder why sulphuric acid cannot be produced through the protonaction of sulphate ions, for example, by mixing HCl and Na2SO4.
After mixing the salt and acid, concentrated sulphuric acid can be produced by heating up the liquid.
However, this method is not commonly used, or not even used, why?