Preparation of 1M Sodium Phosphate Dibasic from Sodium Phosphate Dibasic Dihydrate (Na2HPO4.2H2O)

OVERVIEW
A 1M Sodium phosphate dibasic solution can be prepared by dissolving 177.9897 g of Sodium phosphate dibasic dihydrate (Na2HPO4.2H2O, Molecular weight 177.9897) in deionized water in a total volume of 1000 ml.

REQUIREMENTS

Reagents and solutions
Sodium phosphate dibasic, dihydrate (Na2HPO4.2H2O) (Molecular weight: 177.9897)
Deionized / Distilled water

Equipment and disposables
Measuring cylinder
Conical flask / Beaker
Magnetic stirrer
Spatula

COMPOSITION
1 M Sodium phosphate dibasic

OBJECTIVE
Preparation of 1000 ml of 1M Sodium phosphate dibasic solution in water from Sodium phosphate dibasic  dihydrate (Na₂HPO₄.2H₂O)

PREPARATION:

Step 1: To prepare 1000 ml of 1M Sodium phosphate dibasic solution, weigh out 177.99 g of  Sodium phosphate dibasic (Molecular weight = 177.9897). Transfer to a 2 L  beaker/conical flask. Add 800 ml of deionized/distilled water. Mix until sodium phosphate dibasic dissolves completely.

Tip
One can use manual shaking using a glass pipette to mix the ingredients. Magnetic stirrer makes the dissolving process easy and convenient.

Precaution
Do not dissolve in 1000 ml of deionized / Distilled water. In most cases, solution volume increases when a large amount of solute dissolves in the solvent.

Step 2: Adjust the volume to 1000 ml with deionized / Distilled water. Mix it again.

Note:
The solution will appear colorless and transparent.

Step 4: Transfer the solution to an autoclavable bottle. Sterilize the solution by autoclaving (20 minutes at 15 lb/sq.in. (psi) from 121-124°C on liquid cycle).

STORAGE
Solution can be stored at room temperature.

APPLICATIONS

• Preparation of Sodium phosphate buffer