These are easy instructions for making sodium carbonate, also known as washing soda or soda ash, from baking soda or sodium bicarbonate.
Make Sodium Carbonate
Sodium bicarbonate is CHNaO3, while sodium carbonate is Na2CO3. Simply heat baking soda or sodium bicarbonate in a 200 F oven for about an hour. Carbon dioxide and water will be given off, leaving dry sodium carbonate. This is the soda ash.
The chemical reaction for the process is:
2 NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)
The compound will readily absorb water, forming the hydrate (returning to baking soda). You can store the dry sodium carbonate in a sealed container or with a desiccant to keep it dry or allow it to form the hydrate, as desired.
While sodium carbonate is fairly stable, it slowly decomposes in dry air to form sodium oxide and carbon dioxide. The decomposition reaction can be accelerated by heating the washing soda to 851 C (1124 K).
Key Takeaways: Baking and Washing Soda
- Sodium bicarbonate (baking soda) and sodium carbonate (washing soda) are similar molecules. The difference is how much water is incorporated into the molecule.
- If you bake baking soda, it decomposes to form washing soda, releasing carbon dioxide and water.
- Over time, washing soda decomposes for form sodium oxide, releasing carbon dioxide. Warmer conditions speed the decomposition process.
Uses for Washing Soda
Washing soda is a good all-purpose cleaner. Its high alkalinity helps it cut grease, soften water, and disinfect surfaces. Keep in mind, sodium carbonate solution irritates the skin and can produce chemical burns in pure form. Wear gloves when using it!
Sodium carbonate is used to adjust swimming pool pH, prevent caking in foods, and as a treatment for ringworm and eczema. It's also used on a commercial scale for making glass and paper products.