The Science bit
Sodium bicarbonate is the
chemical compound with the formula NaHCO3. Because it has long been known and is widely used, the
salt has many other names including
sodium hydrogencarbonate,
sodium bicarb,
baking soda,
bread soda,
cooking soda,
bicarb soda or
bicarbonate of soda. The word
saleratus, from
Latin sal æratus meaning "aerated
salt", was widely used in the 19th century for both sodium bicarbonate and
potassium bicarbonate. The term has now fallen out of common usage.
It is
soluble in water. Sodium bicarbonate is a white solid that is
crystalline but often appears as a fine powder. It has a slight
alkaline taste resembling that of
sodium carbonate. It is a component of the mineral
natron and is found dissolved in many
mineral springs. The natural mineral form is known as
nahcolite. It is also produced artificially.
Production
Main article: Solvay process
NaHCO3 is mainly prepared by the
Solvay process, which is the reaction of
sodium chloride,
ammonia, and
carbon dioxide in water. It is produced on the scale of about 100,000 ton/year (year: 2001).
[1]
Commercial quantities of baking soda are also produced by this method: soda ash, mined in the form of the ore
trona, is dissolved in water and treated with carbon dioxide. Sodium bicarbonate precipitates as a solid from this method:
Na2CO3 + CO2 + H2O → 2 NaHCO3