Properties and Uses of Sodium Bicarbonate
Baking Soda Bicarbonate has Powerful Effects and Myriad Applications
Jan 8, 2009
The number of chemicals in the home abound. Chemistry is at work in the bathroom, kitchen, laundry and medicine cabinet. Sodium bicarbonate is a most useful, versatile and cheaply available substance used in the home and for personal use.
Sodium bicarbonate is obtained by chemical process called the Solvay Process, or more directly by extraction from the ore. It is mildly alkaline and has a wide range of applications.
Sodium bicarbonate has the chemical formula NaHCO3 (see Fig 1). It is known under different household names: baking soda, sodium bicarb or bicarb soda, etc. but better known to chemists as sodium bicarbonate, bicarbonate of soda, sodium hydrogen carbonate, and sodium acid carbonate.
History of Production
The ancient Egyptians first mined the natural deposit called natron, which contains mostly sodium bicarbonate. The mixture was used as a cleansing agent such as soap. It was not until 1791 in France that Leblanc artificially manufactured sodium bicarbonate as we know it today. Later, in 1846, two bakers Dwight and Church refined the process of making baking soda from sodium carbonate and carbon dioxide. The ammonia-soda process was developed into its modern form by Ernest Solvay during the 1860s.
Baking soda is produced on the scale of about 100,000 ton/year (Holleman, A. F.; Wiberg, E. Inorganic Chemistry. Academic Press. San Diego, 2001). It is mainly prepared from the Solvay Process. However, commercial quantities are also produced from soda ash of the ore trona, which is dissolved in water and treated with carbon dioxide. Sodium bicarbonate then precipitates as a solid. The main reaction is:
Na2CO3 + CO2 + H2O -> 2NaHCO3
Key Properties
Sodium bicarbonate has a number of interesting properties, which makes it so versatile and useful:
- Odourless, white crystalline solid or powder
- Slightly alkaline in solution
- Sparingly soluble in water
- Decomposes to sodium carbonate and carbon dioxide on heating
- Has relatively low toxicity
- Non-flammable
- The powder dust is not explosive
Applications of Baking Soda
Baking soda is a weak base and therefore not a powerful detergent compared to a strong alkali which breaks down fat. However, it does remove dirt with the properties already alluded to. In order to prevent any alkali from damaging your skin, rubber gloves should be worn.
For the Home:
- Cleaning agent - fridges, garbage disposals, etc.
- Water softener – use in washing machines and for washing dishes
- Deodorizing - shoes, footwear cupboards, carpet refresher
- Fire extinguisher – forms a smothering soapy foam
- Polishing - removes dirt without damaging high hardness materials such as stainless steel or iron
- Mixed with sugar - acts as an effective pesticide for roaches and silverfish
In the Kitchen:
- Baking – used as a leavening agent, the carbon dioxide generated makes the dough rise
- Cooking – quickly softens vegetables such as french beans and broccoli
For Care of the Body:
- Use as a teeth whitener - brush teeth with a paste of bicarb soda and water
- Sodium bicarbonate ear drops
- Stomach reliever - spoonful in cool glass of water
- Eczema reliever - half-cup in hot bath from 15 to 20 minutes
- Also good for the throat, painful gums, insect bites, and warts
- Use in cosmetics and personal care products
For Emergencies:
Sodium bicarbonate can neutralize or reduce acids in the blood, or urine. It may be used in emergency medical situations (heart attacks, serious kidney or lung problems) to correct the normal acid-base balance in the blood or as an aid in treating overdoses with certain types of medications.
Impurities in Sodium Bicarbonate
Sodium bicarbonate is a very versatile substance and the list of uses given is by no means exhaustive, but represents some of the better known uses. People should be aware that when using for medicinal purposes, producer's baking soda contains traces of aluminium. This author contacted one retailer (McKenzie's Foods) who quoted their sodium bicarbonate product indeed has aluminium, naturally occurring at maximum levels of 0.2ppm (0.2 mg per kg).
 |
 |
