Which of the following is oxidised by $SO_2$?

Identify the redox reactions among the following and determine the oxidizing and reducing agents in them:
$(a) 3HCl_{(aq)} + HNO_{3_{(aq)}} \to Cl_{2_{(g)}} + NOCl_{(g)} + 2H_2O_{(l)}$
$(b) HgCl_{2_{(aq)}} + 2KI_{(aq)} \to HgI_{2_{(s)}} + 2KCl_{(aq)}$
$(c) Fe_2O_{3_{(s)}} + 3CO_{(g)} \xrightarrow{\Delta} 2Fe_{(s)} + 3CO_{2_{(g)}}$

Which of the following reactions is a decomposition redox reaction?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$CaSO_3(s) + H_2SO_4(aq) \longrightarrow CaSO_4(s) + SO_2(g) + H_2O(l)$

Justify that the following reactions are redox reactions:
$(a) \ CuO_{(s)} + H_{2(g)} \to Cu_{(s)} + H_2O_{(g)}$
$(b) \ Fe_2O_{3(s)} + 3CO_{(g)} \to 2Fe_{(s)} + 3CO_{2(g)}$
$(c) \ 4BCl_{3(g)} + 3LiAlH_{4(s)} \to 2B_2H_{6(g)} + 3LiCl_{(s)} + 3AlCl_{3(s)}$
$(d) \ 2K_{(s)} + F_{2(g)} \to 2K^+F^-_{(s)}$
$(e) \ 4NH_{3(g)} + 5O_{2(g)} \to 4NO_{(g)} + 6H_2O_{(g)}$

$KI$ is oxidised into $I_2$ by using the reagent