Which of the following will not change the orange colour of $K_2Cr_2O_7$ into green colour in an acidic medium?

Aqueous sulphite reacts with dilute sulphuric acid to form $X_{(g)}$. The liberated $X_{(g)}$ is passed into acidified $KMnO_4$ solution. What is the oxidation state of $Mn$ in the product formed?

In the reaction between moist $SO_2$ and acidified permanganate solution:

Match List-$I$ with List-$II$.

List-$I$ (Types of redox reactions)	List-$II$ (Examples)
$a.$ Combination reaction	$(i)$ $Cl_{2(g)} + 2Br^-_{(aq)} \rightarrow 2Cl^-_{(aq)} + Br_{2(l)}$
$b.$ Decomposition reaction	$(ii)$ $2H_2O_{2(aq)} \rightarrow 2H_2O_{(l)} + O_{2(g)}$
$c.$ Displacement reaction	$(iii)$ $CH_{4(g)} + 2O_{2(g)} \xrightarrow{\Delta} CO_{2(g)} + 2H_2O_{(l)}$
$d.$ Disproportionation reaction	$(iv)$ $2H_2O_{(l)} \xrightarrow{\text{electrolysis}} 2H_{2(g)} + O_{2(g)}$

Choose the correct answer from the options given below.

$A_2O_x$ is oxidized to $AO_3^-$ by $MnO_4^-$ in acidic medium. If $1.5 \times 10^{-3} \text{ mole}$ of $A_2O_x$ requires $40 \text{ mL}$ of $0.03 \text{ M } KMnO_4$ solution in acidic medium,which of the following statement$(s)$ is/are correct?

Iron is dropped in dilute $HNO_3$,it gives: