In the neutral or faintly alkaline medium,$KMnO_4$ oxidises iodide into iodate. The change in oxidation state of manganese in this reaction is from?

The coefficients $x, y, p, q,$ and $r$ in the following balanced equation are respectively:
$xMnO_4^{2-}{_{\text{(aq)}}} + yH_2O_{\text{(l)}} \rightarrow pMnO_2{_{\text{(s)}}} + qMnO_4^{-}{_{\text{(aq)}}} + rOH^{-}{_{\text{(aq)}}}$

Number of moles of $MnO_4^-$ required to oxidize one mole of ferrous oxalate completely in acidic medium will be .......... $moles$.

In acidic medium,iodide $(I^{-})$ is oxidized to iodine $(I_2)$ by $KMnO_4$. What is the change in the oxidation number of manganese in this reaction?

In the redox reaction
$x \ MnO + y \ PbO_2 + z \ HNO_3 \to a \ HMnO_4 + b \ Pb(NO_3)_2 + c \ H_2O$
Find the values of $x, y, z$.

$6 Fe_3O_4 + 2 MnO_4^- + H_2O \to 9 Fe_2O_3 + 2 MnO_2 + 2 OH^-$ Calculate the equivalent weight of $Fe_3O_4$ in the above equation.