Question

When potassium permanganate is added to acidulated solution of ferrous sulphate
(A) Potassium ion is reduced
(B) Manganese ions is oxidised
(C) Ferrous ion is oxidised
(D) Acid is neutralised

Answer 1

Hint : Reaction of Ferrous sulphate with acidified Potassium permanganate is an example of a redox reaction. In redox reactions, oxidation and reduction take place simultaneously. In this type of reaction, one species gets oxidised and the other gets reduced.

Complete Step By Step Answer:
A redox reaction is given as a chemical reaction which is governed via transfer of electrons between two atoms or molecules participating in the reaction. This transfer of electrons is observed by calculating the changes that occur in the oxidation states of the reacting species.
Potassium permanganate is purple in color, when you add acidified potassium permanganate into a ferrous sulphate solution, then the purple colour of the solution disappeared from the solution as the permanganate ion acts as an oxidising agent in the solution and is reduced and the ferrous ion is oxidised by converting the ferrous ion into ferric ion. The purple permanganate changes to colourless manganese sulphate. In presence of an acid potassium permanganate acts as a strong acid. Since Potassium permanganate is an unstable compound, it decomposes in presence of ferrous sulphate by changing its color from purple to colorless. In this reaction, $MnO_4^{2 - }$ changes to $M{n^{2 + }}$ and the oxygen atom oxidised the $F{e^{2 + }}$ to $F{e^{3 + }}$ . The complete reaction for this is given as:
$MnO_4^{2 - } + 5F{e^{2 + }} + 8{H^ + } \to M{n^{2 + }} + 5F{e^{3 + }} + 4{H_2}O$
When potassium permanganate is added to the acidulated solution of ferrous sulphate, ferrous ion is oxidised and the acid is neutralised.
Therefore, the correct options are (C) and (D).

Note :
Oxidation numbers represent the potential charge present on an atom in its ionic form. If the atom's oxidation is decreased in a reaction, then it is said to get reduced. If it increases, then the atom is said to get oxidized.