Procedure for preparation and standardization 0.5 N Hydrochloric Acid

1. OBJECTIVE
To lay down the procedure for preparation and standardization of 0.5 N Hydrochloric Acid

2. SCOPE
This procedure is applicable to Quality Control Department

3. RESPONSIBILITY
• Officer QC
• Manager QC

4. SAFETY INSTRUCTIONS
• Proper handling the apparatus.
• Remember to handle concentrated hydrochloric acid with care as it is highly corrosive and can cause severe burns.
• Wear appropriate protective gear, such as gloves and eye protection, and work in a well-ventilated area.

5. PROCEDURE
5.1 PREPARATION
5.1.1 Determine the molarity of the concentrated hydrochloric acid (HCl) solution you have. The density and %age of HCl is typically listed on the bottle or container.
5.1.2 Calculate the amount of concentrated HCl solution you will need to make 1 liter of 1N HCl solution. To do this, you can use the following formula:
Stock bottle of 37% HCL.
Determination of molarity of 37% HCL V/V
As Molarity = % by weight x 10 x density x 1000/ mol. weight
Put the values
Molarity = 37 x 10 x 1.18 / 36.5 = 11.96 ~ 12M

Compounding 1 liter of 1N Solution
M1V1 = M2V2
(0.5)(1000) = (12) (x)

x = (0.5) (1000) / 12
x = 41.66 ml

Therefore add 41.66 ml of 37% HCL to 1 liter
5.1.4 Measure out the calculated amount of concentrated HCl solution using a graduated cylinder or pipette.
5.1.5 Add the concentrated HCl solution to a 1-liter volumetric flask containing almost 40ml of water.
5.1.6 Dilute the concentrated HCl solution with distilled water until the volumetric flask is filled to the 1-liter mark.
5.1.7 Gently mix the solution by inverting the flask several times.
5.2 STANDARDIZATION
5.2.1 Accurately weigh about 2.5 g of tromethamine, previously dried at 105 for 3 hours.
5.2.2 Dissolve in 50 mL of water, and add 2 drops of bromocresol green TS. Titrate with 1 N hydrochloric acid to a pale yellow endpoint.
5.2.3 Each 121.14 mg of tromethamine is equivalent to 1 mL of 0.5 N hydrochloric acid.
5.2.4 And calculate the normality by the following formula:
mg tromethamine
N= ————————————-
121.14 x ml of HCl

6. RELATED DOCUMENTS
N/A

7. DISTRIBUTION INDEX
Original Copy will be retained by Quality Assurance Department.

8. ABBREVIATIONS
Q.C Quality Control Department
TS Test Solution
Gm Gram
ml Milliliter

9. REVISION HISTORY