a. \(\boxed{\mathrm{NaO}_{2}(s) + 2 \mathrm{H}_{2} \mathrm{O}(l) \rightarrow 2 \mathrm{NaOH}(aq) + \mathrm{O}_{2}(g) + \mathrm{H}_{2} \mathrm{O}_{2}(aq)}\)
b. \(\boxed{\mathrm{Fe}_{2} \mathrm{O}_{3}(s) + 6 \mathrm{HBr}(aq) \rightarrow 2 \mathrm{FeBr}_{3}(aq) + 3 \mathrm{H}_{2} \mathrm{O}(l)}\)
c. \(\boxed{2 \mathrm{H}_{2} \mathrm{~S}(g) + 3 \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{SO}_{2}(g) + 2 \mathrm{H}_{2} \mathrm{O}(g)}\)