Which ion is colourless?

Which of the following shows maximum number of oxidation states?

2Zn + O₂ $$ \to $$ 2ZnO;  $$\Delta $$G^o = $$-$$ 616 J
2Zn + S₂ $$ \to $$ 2ZnS;  $$\Delta $$G^o = $$-$$ 293 J
S₂ + 2O₂ $$ \to $$ 2SO₂;   $$\Delta $$G^o = $$-$$408 J
$$\Delta $$G^o for the following reaction
2ZnS + 3O₂ $$ \to $$  2ZnO + 2SO₂ is

Volume of CO₂ obtained by the complete decomposition of 9.85 g of BaCO₃ is