Question

20
10
Determine the molarity of the given KMnO4 solution with the help of supplied
M
Mohr's salt solution.
20
अथवा /OR
2TO
विधि सेजात​

Answer 1

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Answer 2

Given: Mohr's salt of molarity M/20

To find: Molarity of given solution of potassium permanganate

Explanation:

Mohr's salt: ferrous ammonium sulphate

The titration of Mohr's salt with potassium permanganate is a classic example of oxidation- reduction reaction (Redox reaction). In this reaction, potassium permanganate get reduced hence act as Oxidising agent whereas ferrous ion of Mohr's salt gets oxidized to ferric ion  therefore act as a reducing agent.

Potassium permanganate, which is dark pink in color, act as a self indicator in the reaction.

Procedure:

1. Prepare 100 ml solution of Mohr's salt of M/20 strength.
2. Pipette out 50 ml of Mohr's salt solution in a clean conical flask and add few drops of Sulphuric acid in it. This solution is colorless.
3. Fill the burette with potassium permanganate solution of unknown strength. Note the initial reading of burette (preferably zero ml).
4. Titrate the solution of Mohr's salt with Potassium permanganate until there is permanent light pink color.
5. Stop the titration and note the reading of burette. This gives the volume of potassium permanganate consumed.

Calculations:

Molarity of Mohr's salt (M1) = 0.05

Volume of Mohr's salt (V1) = 50 ml

Molarity of potassium permanganate (M2) = Let M

Volume of Potassium permanganate (v2) =  final reading of burette

$M_{1} V_{1} = M_{2} V_{2}$