How many electrons are lost in the following transformation?
$3Fe + 4H_2O \to Fe_3O_4 + 4H_2$

Observe the following reaction:
$aP_4{_{\text{(s)}}} + bOH^{-}{_{\text{(aq)}}} + cH_2O_{\text{(l)}} \rightarrow dPH_3{_{\text{(g)}}} + eH_2PO_2^{-}{_{\text{(aq)}}}$
The values of $a, b, c,$ and $d$ are respectively:

The product of oxidation of $I^-$ ion by $MnO_4^-$ in alkaline medium is

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$3PbS \downarrow + 8HNO_3(dil.) \longrightarrow 3Pb(NO_3)_2 + 3S + 2NO \uparrow $

In neutral or faintly alkaline solution,$8$ moles of permanganate anion quantitatively oxidize thiosulphate anions to produce $X$ moles of a sulphur containing product. The magnitude of $X$ is

How many moles of $H_2O_2$ are required to decolorize $1 \ mol$ of $KMnO_4$ in an acidic medium (in $.5$)?