Identify the substance oxidised, reduced, oxidising agent and reducing agent for each of the following reactions: (a) $2 \mathrm{AgBr}_{(s)}+\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{2}(\mathrm{aq}) \rightarrow 2 \mathrm{Ag}_{(s)}+2 \mathrm{HBr}_{(\mathrm{aq})}+\mathrm{C}_{6} \mathrm{H}_{4} \mathrm{O}_{2}(\mathrm{aq})$ (b) $H C H O_{(l)}+2\left[A g\left(N H_{3}\right)_{2}\right]_{(a q)}^{+}+3 O H_{(a q)}^{-} \rightarrow 2 A g_{(s)}+H C O O_{(a q)}^{-}+$ $4 \mathrm{NH}_{3}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}_{(l)}$ (c) $\mathrm{HCHO}_{(l)}+2 \mathrm{Cu}_{(a q)}^{2+}+5 \mathrm{OH}_{(a q)}^{-} \rightarrow \mathrm{Cu}_{2} \mathrm{O}_{(s)}+\mathrm{HCOO}_{(a q)}^{-}+3 \mathrm{H}_{2} \mathrm{O}_{(l)}$ (d) $N_{2} H_{4(l)}+2 \mathrm{H}_{2} \mathrm{O}_{2}(l) \rightarrow N_{2}(g)+4 \mathrm{H}_{2} \mathrm{O}_{(l)}$ (e) $\mathrm{Pb}_{(s)}+\mathrm{PbO}_{2(s)}+2 \mathrm{H}_{2} \mathrm{SO}_{4(a q)} \rightarrow 2 \mathrm{PbSO}_{4}(a q)+2 \mathrm{H}_{2} \mathrm{O}_{(l)}$