The reaction of $Na_2S_2O_3$ with iodine gives

$x, y$ and $z$ are respectively:
$MnO_4^- + x e^- \xrightarrow{\text{Alkaline medium}} MnO_4^{2-}$
$MnO_4^- + y e^- \xrightarrow{\text{Acidic medium}} Mn^{2+}$
$MnO_4^- + z e^- \xrightarrow{\text{Neutral medium}} MnO_2$

Reduction of the metal centre in aqueous permanganate ion involves

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Pb_3O_4 + 4HNO_3 \rightarrow 2Pb(NO_3)_2 + PbO_2 + 2H_2O$

Consider the reactions:
$2S_2O_3^{2-}{(aq)} + I_{2(s)} \to S_4O_6^{2-}{(aq)} + 2I^{-}{(aq)}$
$S_2O_3^{2-}{(aq)} + 2Br_{2(l)} + 5H_2O_{(l)} \to 2SO_4^{2-}{(aq)} + 4Br^{-}{(aq)} + 10H^{+}{(aq)}$
Why does the same reductant,thiosulphate,react differently with iodine and bromine?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Na_2CO_3 + Pb(NO_3)_2 \longrightarrow PbCO_3 \downarrow + 2NaNO_3$