點解soda powder(梳打粉)係焗麵個陣會發脹?

NaHCO3 is mainly prepared by the Solvay process, which is the reaction of calcium carbonate, sodium chloride, ammonia, and carbon dioxide in water. It is produced on the scale of about 100,000 ton/year (as of 2001).[2]

NaHCO3 may be obtained by the reaction of carbon dioxide with an aqueous solution of sodium hydroxide. The initial reaction produces sodium carbonate:

CO2 + 2NaOH → Na2CO3 + H2O
Further addition of carbon dioxide produces sodium bicarbonate, which at sufficiently high concentration will precipitate out of solution:

Na2CO3 + CO2 + H2O → 2NaHCO3
Commercial quantities of baking soda are also produced by a similar 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 → 2NaHCO3

2009-02-11 11:38:15 補充：
Sodium bicarbonate is primarily used in cooking (baking) where it reacts with other components to release carbon dioxide, that helps dough "rise".