Preparation and Standardization Of 1.0 M Sodium Hydroxide

1.0 OBJECTIVE 

To lay down the procedure for the Preparation and Standardization Of 1.0 M Sodium Hydroxide

2.0 SCOPE

This SOP is applicable to Preparation and Standardization Of 1.0 M Sodium Hydroxide

3.0 BACKGROUND 

NIL

4.0 RESPONSIBILITY

4.1 QC-Chemist 

4.2 Head-QC

5.0 PROCEDURE

5.1 Preparation:

Dissolve 42 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 1 M sodium hydroxide ≡ 0.2042 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=24.8ml

W=0.50612 gm

= 0.50612x0.1

   24.8x0.02042

= 0.999415 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