Preparation and Standardization of 0.004 M Benzethonium Chloride

Benzethonium Chloride Solution Preparation

• Dissolve 1.792 g of benzethonium chloride, previously dried to constant weight at 105°, in the sufficient water to produce 1000 ml.
• Standardize the solution in the following manner.

Benzethonium Chloride Solution Standardization

• Weigh accurately about 570 mg of Sodium lauryl sulfate, previously dried at about 105°C for about 1 hour.
• Transfer it to a cleaned and dried 500 ml volumetric flask and add 300 ml of water with gentle stirring.
• Make up the volume 500 ml with water. Mix solution thoroughly (Solution –A)
• Take 20 ml of solution-A add 10 ml of water, 15 ml chloroform, 10 ml dilute sulphuric acid and add 1 ml dimethyl yellow-orcet blue-B solution as indicator.
• Titrate with Benzothonium chloride solution
• Calculate the molarity of solution by the following formula:

                                                                              W (in gms) x 20
Molarity of 0.004 M Benzothonium chloride = ------------------------------
                                                                            BR x 0.28838 x 500
Also see: Determination of Shelf Life of Solutions in Laboratory