The number of moles of $KMnO_4$ that will be needed to react completely with one mole of ferrous oxalate $FeC_2O_4$ in acidic solution is

One mole of potassium dichromate completely oxidises the following number of moles of ferrous sulphate in acidic medium.

Reaction of silver nitrate solution with phosphorous acid produces:

In an experiment,$50 \ mL$ of $0.1 \ M$ solution of a metal salt reacted with $25 \ mL$ of $0.1 \ M$ solution of sodium sulphite. The half-equation for the oxidation of sulphite ion is $SO_3^{2-}{(aq)} + H_2O_{(l)} \to SO_4^{2-}{(aq)} + 2H^{+}{(aq)} + 2e^-$. If the oxidation number of the metal in the salt was $3$,what would be the new oxidation number of the metal?

How many electrons are involved in the following redox reaction?
$Cr_2O_7^{2-} + Fe^{2+} + C_2O_4^{2-} \to Cr^{3+} + Fe^{3+} + CO_2$ (Unbalanced)

The dark purple colour of $KMnO_4$ disappears in the titration with oxalic acid in acidic medium. The overall change in the oxidation number of manganese in the reaction is.