For the reaction $4Fe + 3O_2 \to 4Fe^{3+} + 6O^{2-}$,which of the following statements is incorrect?

By passing $H_2S$ gas in acidified $KMnO_4$ solution,we get

Given below are two statements:
Statement-$I$ : Heating $NaCl$ with concentrated $H_2SO_4$ and $MnO_2$ results in oxidation of $Mn$.
Statement-$II$ : Heating $NaI$ with concentrated $H_2SO_4$ and $MnO_2$ results in reduction of $Mn$.
In light of the above statements, choose the most appropriate answer from the options given below:

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

Assign $A, B, C, D$ from the given type of reaction.
$Sr(AcO)_2 + Ag_2SO_4 \longrightarrow 2AcOAg \downarrow + SrSO_4 \downarrow$

To measure the quantity of $MnCl_2$ dissolved in an aqueous solution,it was completely converted to $KMnO_4$ using the reaction,
$MnCl_2 + K_2S_2O_8 + H_2O \longrightarrow KMnO_4 + H_2SO_4 + HCl$ (equation not balanced).
Few drops of concentrated $HCl$ were added to this solution and gently warmed. Further,oxalic acid $(225 \ mg)$ was added in portions till the colour of the permanganate ion disappeared. The quantity of $MnCl_2$ (in $mg$) present in the initial solution is . . . . . . . . . (Atomic weights in $g \ mol^{-1}: Mn = 55, Cl = 35.5$ )