Procedure for preparation and standardization 0.1 M Sodium Nitrite

1. OBJECTIVE
To lay down the procedure for preparation and standardization of 0.1 M Sodium Nitrite

2. SCOPE
This procedure is applicable to Quality Control Department

3. RESPONSIBILITY
• Officer QC
• Manager QC

4. SAFETY INSTRUCTIONS
• Proper handling the apparatus.
• Proper handling the chemicals
• Always wear appropriate personal protective equipment when handling this chemical.
• Always handle NaNO2 with care and follow proper safety protocols. NaNO2 is toxic and can be harmful if ingested, inhaled, or absorbed through the skin. It is also a strong oxidizing agent and can react violently with reducing agents. It should be stored in a tightly sealed container away from other chemicals.

5. PROCEDURE
5.1 PREPARATION
5.1.1 Determine the molecular weight of NaNO2, which is 69 g/mol.
5.1.2 Decide on the volume of the solution you want to prepare. Let’s say you want to make 500 mL of solution.
5.1.3 Calculate the number of moles of NaNO2 needed for a 0.1M solution. M represents the molarity of the solution, which is defined as the number of moles of solute dissolved per liter of solution. For NaNO2, the molar mass is 69 g/mol. Therefore, to prepare a 0.1M solution, you need 0.1 moles of NaNO2 per liter of solution
The mass of NaNO2 required can be calculated using the following formula:
      Mass (g) = moles x molecular weight (g/mol)
      Mass (g) = 0.1 moles x 69 g/mol
      Mass (g) = 6.9 g
5.1.4 Weigh out 6.9 grams of NaNO2 using a scale.
5.1.5 Add distilled water to a volumetric flask to bring the volume up to 500 mL.
5.1.6 Carefully add the 6.95 grams of NaNO2 to the volumetric flask and stir until the NaNO2 dissolves completely.
5.1.7 Once the NaNO2 is completely dissolved, add more distilled water to bring the solution up to the mark on the volumetric flask, which indicates a total volume of 1000 mL.
5.1.8 Mix the solution thoroughly to ensure that the NaNO2 is evenly distributed throughout the solution
5.2 STANDARDIZATION
5.2.1 Accurately weigh about 500 mg of USP Sulfanilamide RS, previously dried at 105 for 3 hours, and transfer to a suitable beaker.
5.2.2 Add 20 mL of hydrochloric acid and 50 mL of water, stir until dissolved, and cool to 15 . Maintaining the temperature at about 15 , titrate slowly with the sodium nitrite solution, placing the burette tip below the surface of the solution to preclude air oxidation of the sodium nitrite, and stir the solution gently with a magnetic stirrer, but avoid pulling a vortex of air beneath the surface.
5.2.3 Use the indicator specified in the individual monograph, or, if a potentiometric procedure is specified, determine the endpoint electrometrically, using platinum–calomel or platinum–platinum electrodes.
5.2.4 When the titration is within 1 mL of the endpoint, add the titrant in 0.1-mL portions, and allow 1 minute between additions. Each 17.22 mg of sulfanilamide is equivalent to 1 mL of 0.1000 M sodium nitrite.
5.2.5 And calculate the normality by the following formula:

         mg Sulfanilamide
N= ——————————————————
         172.22 x ml NaNO₂

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