SOP FOR PREPARATION AND STANDARDIZATION OF 0.1M AMMONIUM THIOCYANATE

Preparation
Dissolve 7.612 g in sufficient water to produce 1000 ml
Standardisation
To 20 ml of 0.1M silver nitrate VS add 25 ml of water, 2 ml of 2M nitric acid and 2 ml of ammonium iron(III) sulphate solution R2 and titrate with the ammonium thiocyanate solution until a reddish yellow colour is obtained.
Each ml of 0.1M silver nitrate VS is equivalent to 7.612 mg of NH4SCN.
Perform a duplicate and calculate the molarity factor (MF)
Note down the average value
Calculation :--------------

Note:
1) Restandardise before use
2) Discard the solution after 30 days.
3) For storage and labeling follow the general procedure.