What determines if in a reaction between sodium chloride and sulfuric acid you will get sodium bisulfate or sodium sulfate?
I presume you mean the reaction between sodium hydroxide and sulfuric acid.
If 2 equiv sodium hydroxide are used:
If 1 equiv sodium hydroxide is used:
Both reactions are balanced with respect to mass and charge (and they must be). The difference is the stoichiometry. Only the 1 equiv sodium hydroxide was added in the 2nd equation, therefore, the diprotic sulfuric acid reacted to give sodium bisulfate,