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Preparation and Standardization of 0.1 M Sodium Methoxide


Preparation and standardisation of 0.1 M Sodium Methoxide solution using Benzoic acid and Thymolphthalein solution as indicator that is used for pharmaceutical analysis.

Sodium Methoxide Solution Preparation

•  Cool 150 ml of anhydrous methanol in ice water and add, in small portions, about 2.5 g of freshly cut sodium. 
•  When the metal has dissolved, add sufficient toluene, previously dried over sodium wire to produce 1000 ml. 
•  Standardize the solution in the following manner immediately before use.

Sodium Methoxide Solution Standardization

•  Weigh accurately about 0.4 g of benzoic acid, dissolve in 80 ml of dimethyl formamide.
•  Add 0.15 ml of thymolphthalein solution and titrate with sodium methoxide solution to a blue end point.
•  Protect the solution from atmospheric carbon dioxide throughout the titration. 
•  Perform  a blank determination and make any necessary correction.
• 1 ml of 0.1 M sodium methoxide is equivalent to 0.01221 g of  C7H6O2.
• Store protected from carbon dioxide and moisture.
• Calculate molarity of solution by following formula:
                   C7H6O2 in mg
M = ------------------------------------------
         Sodium Methoxide in ml  x 12.21

Also see: Determination of Shelf Life of Solutions in Laboratory

Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of Pharmaceutical Guidelines, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
Email: .moc.enilediugamrahp@ofni Need Help: Ask Question


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