In the thermal decomposition of a metal carbonate,the oxidation state of the metal changes if the metal is

Identify the correct statements about the following stoichiometric equation.
$aP_4 + bOH^{-} + cH_2O \longrightarrow dPH_3 + eH_2PO_2^{-}$
$I$. $a+b+c=5$
$II$. $b+c-e=3$
$III$. The oxidation state of $P$ in $H_2PO_2^{-}$ is $+1$.

$MnO_4^- + C_2O_4^{2-} + H^+ \to Mn^{2+} + CO_2 + H_2O$ :
What are the correct stoichiometric coefficients for the balanced redox reaction?

In the redox reaction $N_2H_4 + ClO_3^- \to NO + Cl^-$ (in basic medium),how many electrons are added in the reduction half-reaction based on the difference in oxidation states?

In alkaline medium,what will be the equivalent weight of $I_2$ on its conversion to iodate ion $(IO_3^-)$?

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 $Mn^{2+}$?