balance equation for sodium sulfate + hydrochloric acid = sodium chloride + water +Sulfur dioxide ?

Answer 1

I prefer to do it this way.

Na2SO4 + 2HCl ==> 2NaCl + H2SO4
Then H2SO4 decomposes by
H2SO4 ==> H2O + SO3
Then SO3 decomposes by
2SO3 --> 2SO2 + O2

You can put all of this together as
2Na2SO4 + 4HCl ==> 4NaCl + 2H2O + 2SO2 + O2