Dissolve 17g of silver nitrate in sufficient chloride free water to produce 1000 ml.
Weigh accurately about 0.1g sodium chloride, previously dried at about 110º C for 2 hours and dissolve in 5 ml of water. Add 5 ml of glacial acetic acid, 50 ml of methanol and 0.15 ml of eosin solution. Titrate with silver nitrate solution with constant stirring to purple end point.
Each ml of 0.1 M silver nitrate ≡ 0.005844 g of sodium chloride.
Perform a duplicate and calculate the Molarity factor (MF)
Note down the average value
MF = W/0.005844 X V
W = Weight of sodium chloride in gm.
V = Volume of silver nitrate solution consumed in ml.
1) Restandardise before use
2) Discard the solution after 30 days.
Store in amber bottle with well fitted suitable stoppers which prevents access to atmospheric carbon dioxide.