The heating of $(NH_4)_2Cr_2O_7$ produces another chromium compound along with $N_2$ gas. The change of the oxidation state of $Cr$ in the reaction is

The reaction of bromine water with $SO_2$ produces .......

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Pb(NO_3)_2 \xrightarrow{\Delta} PbO + NO_2 + O_2$

When sulphur dioxide is passed in an acidified $K_{2}Cr_{2}O_{7}$ solution,the oxidation state of sulphur is changed from

The equivalent weight of $KIO_3$ in the given reaction is ($M=$ molecular mass) :
$2 Cr(OH)_3 + 4 OH^{-} + KIO_3 \rightarrow 2 CrO_4^{2-} + 5 H_2O + KI$

Manganese ions $(Mn^{2+})$ can be oxidised by persulphate ions $(S_2O_8^{2-})$ according to the following half-equations:
$S_2O_8^{2-} + 2e^- \longrightarrow 2SO_4^{2-}$
$Mn^{2+} + 4H_2O \longrightarrow MnO_4^- + 8H^+ + 5e^-$
How many moles of $S_2O_8^{2-}$ are required to oxidise $1 \ mole$ of $Mn^{2+}$?