Preparation and Standardization of 0.5 M Methanolic Hydrochloric Acid

Methanolic Hydrochloric Acid Solution Preparation

• Take 40 ml of water in a 1000 ml volumetric flask.
• Slowly add 43 ml of hydrochloric acid.
• Cool and add methanol to volume.
• Standardize the solution in the following manner.

Methanolic Hydrochloric Acid Solution Standardization

• Weigh accurately about 800 mg of anhydrous sodium carbonate, previously heated at about 270°C for 1 hour.
• Dissolve it in 100 ml of water and add 0.1 ml of methyl red solution.
• Add the acid slowly from a burette, with constant stirring, until the solution becomes faintly pink.
• Heat the solution to boiling, cool and continue the titration.
• Heat again to boiling and titrate further as necessary until the faint pink color is no longer affected by continued boiling.
• 1 ml of 0.5 M hydrochloric acid is equivalent to 0.02650 g of Na2CO3.
• Calculate the molarity of solution by the following formula:

             Na2CO3 in mg
M = --------------------------

          HCl in ml x 26.50
Also see: Determination of Shelf Life of Solutions in Laboratory