Question

Need explanation of this practical, To prepare M/20 solution of ferrous ammonium sulphate ( Mohr's salt ) with the help of this solution, determine the molarity an strength of the given solution of potassium permanganate !! ​

Answer 1

Answer:

Explanation:

KMnO4 is a self-indicator.

Colourless to permanent pink colour (KMnO4 in burette).

Prepare 250 ml of M/20 Mohr’s salt solution by dissolving 4.9 g of Mohr’s salt in water 20 as described in experiment 11.3. Rinse the pipette with the M/20 Mohr’s salt solution and pipette out 20.0 ml of it in a washed titration flask.

Rinse and fill the burette with the given KMn04 solution.

Add one test-tube (~ 20 ml) full of dilute sulphuric acid (~ 2 M) to the solution in titration flask.

Note the initial reading of the burette.

Now add KMnO4 solution from the burette till a permanent light pink colour is imparted to the solution in the titration flask on addition of last single drop of KMnO4 solution.

Note the final reading oWeight of watch glass =……. g

Weight of watch glass + Mohr’s salt =…………..g

Weight of Mohr’s salt = 4.90 g

Volume of Mohr’s salt solution prepared = 250 ml

Molarity of Mohr’s salt solution = M/20

Volume of Mohr’s salt solution taken for each titration = 20.0 mlf the burette.

Repeat the above steps 4-5 times to get a set of three concordant readings