In the reduction of dichromate by $Fe(II)$,the number of electrons involved per chromium atom is:

$MnO_4^{-}$ reacts with $A^{x+}$ to form $AO_3^{-}$,$Mn^{2+}$ and $O_2$. One mole of $MnO_4^{-}$ oxidizes $1.25$ moles of $A^{x+}$ to $AO_3^{-}$. What is the value of $x$?

When $KMnO_4$ acts as an oxidizing agent and ultimately forms $MnO_4^{2-}$,$MnO_2$,$Mn_2O_3$,and $Mn^{2+}$,what will be the number of electrons transferred in each case,respectively?

In the reaction between $KI$ and acidic potassium dichromate solution,the oxidation state of chromium in the final product is ........

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

$KMnO_4$ reacts with $H_2O_2$ in an acidic medium. The number of moles of oxygen produced per mole of $KMnO_4$ is