4.1 - Preparation of a Standard Solution of Sodium Carbonate

Materials and Apparatus Required

Chemicals

• Anhydrous sodium carbonate ($Na₂CO₃$)
• Deionised water

Apparatus

• Balance (accurate to 0.01 g)
• Clock glass
• Beaker (250 cm³)
• Stirring rod
• Volumetric flask (250 cm³) and stopper
• Wash bottle
• Filter funnel
• Dropping pipette

Safety Precautions

• Wear safety glasses at all times.
• Sodium carbonate is an irritant to the eyes, skin, and lungs. Handle with care and avoid inhaling the dust.
• Use gloves if handling large amounts of sodium carbonate.

Method

1. Measure 2.65 g of pure anhydrous sodium carbonate on a clock glass using a balance.
2. Transfer the sodium carbonate to a 250 cm³ beaker containing about 50 cm³ of deionised water.
3. Use a wash bottle to rinse any remaining sodium carbonate from the clock glass into the beaker.
4. Stir the mixture with a stirring rod until the sodium carbonate fully dissolves.
5. Wash the stirring rod with deionised water into the beaker to ensure no sodium carbonate is lost.
6. Pour the solution through a funnel into a 250 cm³ volumetric flask.
7. Rinse the beaker several times with deionised water and add the rinsings to the volumetric flask.
8. Rinse the funnel with deionised water, allowing the rinsings to enter the flask.
9. Fill the flask with deionised water until it is about 1 cm below the calibration mark, then add water dropwise using a dropping pipette until the bottom of the meniscus rests on the mark.
10. Stopper the flask and invert it several times to ensure a homogeneous solution.

Results

• Mass of sodium carbonate used: 2.65 g
• The volume of solution: 250 cm³
• Concentration of sodium carbonate solution: 0.1 M

Example Questions with Answers