Standardization of 0.1 N potassium Permanganate

AIM:

To determine the Normality of given sample of 0.1N Potassium permanganate.

REFERENCE:

1. Dr. G.Devalo Rao. Practical pharmaceutical inorganic chemistry.

2. Anees Ahamed Siddiqui and Mohammed Ali. Practical pharmaceutical chemistry.

REQUIREMENTS:

Apparatus : Burette, Iodine flask, Pipette, Reagents : Potassium Permanganate and oxalic acid.

Potassium permanganate is an inorganic compound with the chemical formula KMnO₄. It is a purplish-black crystalline salt, that dissolves in water as  K+ and MnO−an intensely pink to purple solution.

Potassium permanganate is an ionic compound consisting of a potassium cation (K+) and permanganate anion (MnO4-). In permanganate anion (MnO4-) the manganese atom is bonded with four oxygen atoms through three double bonds and one single bond. The oxidation state of manganese in this salt is +7. The crystal structure of solid KMnO4 is orthorhombic. Each MnO4- structure is present in a tetrahedral geometry.

PRINCIPLE:

The principle of standardization of potassium permanganate is based upon redox titration in which strength of an oxidizing agent is estimated by titrating it with a reducing agent and viceversa. Potassium permanganate acts as an strong oxidizing agent in acidic medium that oxidizers oxalic acid in to carbon dioxide . Known strength of oxalic acid is titrated directly with potassium permanganate .End point can be detected with appearance of permanent pink colour potassium permanganate acts as self indicator

2KMnO4 +5H2C2O4 +3H2SO4 →K2SO4 +2MnSO4 +8H2O +10CO2

PROCEDURE: Preparation of 0.1 N Potassium permanganate solution

Dissolve 3.2g of potassium permanganate in 1000ml of water, heat on a water bath for 1 hour, allow to stand for 2 days. Filter the solution through glass wool.

Preparation of 0.1 N Oxalic acid:

6.3 gm of oxalic acid dissolve in 1000 ml of distilled water

Standardisation of 0.1N Potassium permanganate

Take 20 ml of Oxalic acid solution .add 5 ml of 1m sulphuric acid. Warm the mixture to about 70DegC .titrate with potassium permanganate solution taken in the burette. End point is appearance of pink colour that persist for 30 sec

N 1V 1=N 2V 2 

N 2 = N 1V 1/ V 2

REPORT:

The strength of the given solution of potassium permanganate is………………