SODA POWDER INGREDIENTS

Most commercially available baking powders are made up of
sodium bicarbonate (also known as baking soda or bicarbonate of soda)
and one or more acid salts. Two of the ingredients are acidic: they combine with
the sodium bicarbonate and water to produce the gaseous carbon dioxide.
Baking powders also include components to improve
their consistency and stability.
The most important additive is cornstarch,
although potato starch may also be used.
The inert starch serves several functions in baking powder.
Primarily it is used to absorb moisture, and thus prolong shelf life by keeping the powder's additional alkaline and acidic components dry so as
not to react with each other prematurely.
A dry powder also flows and mixes more easily.
Finally, the added bulk allows for more accurate measurements.