Question

Estimation of water of crystallization in Mohr's salt by titrating with KMnOa by pdf

Answer 1

(a) Preparation of 0.05M standard solution of ferrous ammonium sulfate:

The quantity of Mohr’s salt required for the 250ml of the solution having a normality of 0.05N can be calculated as follows.

The molar mass of mohr’s salt = 392 g/mol

Strength = Normality x Equivalent weight

= (1/20) x 392 = 19.6 g/L

For preparing 250ml of N/20 Mohr’s salt solution, Mohr salt required

= (19.6/1000) x 250 = 4.9 gm

   Weigh an empty watch glass using a chemical balance.

   Weigh accurately 4.9gm of Mohr’s salt in a chemical balance.

   With the help of a funnel transfer the Mohr’s salt into the measuring flask.

   Now wash the funnel with distilled water without removing the funnel from the flask.

   Make the solution up to the marked point with distilled water and make sure the Mohr’s salt is fully dissolved.

   This solution is 0.05N standard solution of Mohr’s salt.