sop for preparation and standardization of 1 M Hydrochloric Acid
Transfer accurately measured 85ml of hydrochloric acid in a 1000ml volumetric flask. Dilute in sufficient purified water and make up to the mark with purified water.
As per requirement (consumption history) prepare suitable amount of volumetric solution accordingly.
Weigh accurately about 1.5g of anhydrous sodium carbonate (previously heated at about 270° for 1 hour) and transfer to a conical flask. Dissolve in 100ml of purified water. Add 0.1ml of methyl red solution and titrate with the hydrochloric acid slowly, 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. Note down the volume of hydrochloric acid consumed during titration. Repeat the procedure two more times. Calculate the molarity of the solution by below given formula.
Each ml of 1M hydrochloric acid is equivalent to 0.05299 gm of Na2CO3.
Determine the molarity in triplicate and calculate the average value where the variation is not more than 0.2%. This solution must be standardized frequently every 15 days.
3. Validity: 1 Month from the date of preparation and Re-Standardisation after15 days and when required. (if not used within 15 days solution has to be standardized again just before use.)
4. Precaution – Check the physical appearance and fungal growth, sedimentation or change in color.
5. Storage : Store in glass bottles having well fitted, suitable stoppers.