Sulfuric and nitrate salts would make nitric acid, giving a sulfate salt byproduct, and nitric acid.
2NaNO3 + H2SO4 --> 2HNO3 + Na2SO4
here sodium sulfate has a low solubility and will precipitate out of solution, especially if cold, potassium is very similar, this reaction can be done without distillation, the only problem is that there will be some sulfate salts left in solution (how much depends on your procedure), and with silver these sulfate will form silver sulfate which is insoluble, so if using the nitric on silver it would be best to distill if you do not want to deal with silver sulfates.
Once you make a sulfate salt in my opinion it is hard to change it because it is at the bottom of the food chain (roasting is a tool to overcome this) sorry I don't know a better way to explain than food chain.
Mixing a nitrate salt and Hydrochloric acid will give you a form of aqua regia there is no way around that, but nitric could be made with HCl, but it would be a very dilute nitric, and distill ling would be necessary, here you would usually use a metal in the reaction, like copper, in the reaction flask you are making aqua regia which contains nitric acid and HCL, these will dissolve the copper making copper chloride, and giving off the NOx gasses (NO, NO2, ETC.) it is these gases you would bubble into a receiver and make nitric with,
NO +O2 --> NO2,
NO2 + H2O --> HNO3,
the reason it would be so dilute not only do you have the water your bubbling into to make the nitric acid, but also the water from the HCl distilling off with these gases.
Edit to add: depending on how you distill you could also have HCL come over if your reaction temperature was too high or boiling and carrying over thes acid fumes, then you would again have aqua regia in your nitric acid, ( with this metod you would have to distill properly understanding how to prevent this from happening.
Sulfuric is by far the best method.
Sodium I like better than potassium as far as the reaction for making nitric, but if you want to use the salts potassium sulfate sometime I prefer for a byproduct, either of these salts give no problems for the most parting my experience.
although seems that the platinum group may form some forms of potassium salts, this I do not have enough experience with to answer if there would be reason not to use potassium here to make nitric with, maybe another member can answer that?
