a) Calculate the mass of SO₂ in grams.
b) Calculate the concentration of the remaining species (Na₂SO₃ or HClO₄) without reaction after the reaction is completed.n

If 75.00 mL of 0.30 m Na₂SO₃ (126 g/mol) solution is mixed with 150.0 mL of 0.20 m HClO₄ (100.5 g/mol) solution and boiled and removed SO₂ (64.06 g/mol).
Na₂SO₃ + 2HClO₄ → 2NaClO₄ + H₂O + SO₂