Baking soda is not at all similar to tapioca starch, so you would get a very different result if you replaced one with the other. A more logical substitution for tapioca starch would be corn starch.
No, baking soda is not a starch and mor does it contain starch.
No. Corn starch is usually used as a thickener (for gravies, soups, puddings, etc)., whereas baking soda is used as a puffer-upper for biscuits, cookies and unleavened breads and so on. Use flour as a substitute for corn starch, and baking powder as a substitute for baking soda.
Then it wont come out good.
Because baking soda is NaHCO3 and starch is (C6H10O5). Getting starch in packs of baking soda would be like getting mincemeat in your orange juice. It's not what you're buying.
baking soda
yes
no
Baking powder is a "leavening agent" that makes cakes rise. Baking soda and cream of tartar together do the same job -- they react to make carbon dioxide gas. If you try to make cupcakes without either baking soda, or the combination of baking soda and cream of tartar, your cupcakes will not rise and you will get something close to cookies. Corn starch is a thickener and acts similarly to flour. If you have flour, corn starch may not be necessary.
baking soda
"Baking powder" is a leavening agent and is a mixture of baking soda (sodium bicarbonate), one or more acid salts, and a starch (usually cornstarch).
Baking soda is an alkaline compound that can only be separated chemically.Baking powder however is a mixture of baking soda and an inert starch, usually cornstarch. Cornstarch absorbs moisture in the baking powder, prolonging shelf life and preventing premature reactions in the baking soda. Baking soda and cornstarch can be separated using conventional means, as it is not a compound.
No, instead use lime powder