Preparation and Standardization of 0. 1M Sodium Hydroxide

1.0 OBJECTIVE 

To lay down the procedure for the Preparation and Standardization of 0. 1M Sodium Hydroxide

2.0 SCOPE

This SOP is applicable to Preparation and Standardization of 0. 1M Sodium Hydroxide in company.

3.0 BACKGROUND 

NIL

4.0 RESPONSIBILITY

4.1 QC-Chemist 

4.2 Head-QC

5.0 PROCEDURE 

5.1 Preparation:
Dissolve 4.2 g of Sodium hydroxide in sufficient carbon dioxide-free water to produce 1000 ml.

5.2 Standardization:
Weigh accurately about 0.5g of potassium hydrogen phthalate previously powdered and dried at 120°C for 2 hours. Dissolve it in 75 ml carbon dioxide free water. Add 0.1 ml phenolphthalein solution and titrate with sodium hydroxide solution until a pink colour  changed to blue colour. 

Each ml of 0.1 M sodium hydroxide ≡ 0.02042 gm of potassium hydrogen phthalate.

Perform a duplicate and calculate the molarity factor (MF).
Note down the average value .

5.3 Calculation
MF = W x Molarity of Sodium hydroxide / V x 0.02042
Where
V = Volume of Sodium hydroxide consumed in ml.
W = Weight of potassium Hydrogen phthalate in gram.

V=23.4 ml

W=0.50263 gm

= 0.50263x0.1

   23.4x0.02042

= 0.105190 M

Note :

• Re-standardize before use.
• Store in bottle with well fitted suitable stoppers which prevents access to atmospheric carbon dioxide. Discard the solution after 30 days.
• For storage and labeling follow the general procedure