Preparation and Standardization of 0.1 M Ethanolic Sodium Hydroxide

Ethanolic Sodium Hydroxide Solution Preparation

• Dissolve 4.2 g of sodium hydroxide in 5 ml of water.
• Add sufficient aldehyde-free ethanol to produce 1000 ml.
• Allow the solution to stand in a tightly-stoppered bottle for 24 hours.
• Then quickly decant the clear supernatant liquid into a suitable, tightly-closed container.
• Standardize the solution in the following manner.

Ethanolic Sodium Hydroxide Solution Standardization

• Weigh accurately about 0.6 g of Benzoic acid.
• Dissolve in a mixture of one ml of ethanol (95 percent) and 6 ml of water and titrate with the ethanolic sodium hydroxide solution, using 0.2 ml of Thymolphthalein solution as indicator. 
• 1 ml of 0.1 M ethanolic sodium hydroxide is equivalent to 0.01221g of C7H6O2.
• Store protected from light and moisture.
• Calculate the molarity of solution by the following formula:

                      C7H6O2 in mg
M = ------------------------------------------------------
        Ethanolic Sodium Hydroxide in ml x 12.21
Also see: Determination of Shelf Life of Solutions in Laboratory