Baking powder and salt.
There is no substitute for baking soda.
Yes. Baking soda will work as a substitute in this case.
Not to bake stuff like bread. You can substitute 1 baking soda for 2 baking flour to make reductions. You can substitute 1 baking soda for 1 baking flour for gags (throwing on someone in the shower).
Baking Soda
baking powder.
They would not raise as much.
An excessive amount of baking soda would be double the amount called for in the recipe. This can impart a soda-ish taste to the muffins, cookies, whatever you are baking, but will not usually ruin them.
No. there is a chemical reaction with the baking soda and the other ingredients, not with the flour.
No, baking soda cannot substitute for baking soda because they are the same thing. Baking soda is just another name for sodium bicarbonate.
baking soda
Muffins are fairly forgiving, if I was doing it, 1 teaspoon of oil, 2 tablespoons of water or milk and 1/8 teaspoon of baking soda or baking powder, whichever the recipe calls for.
You cannot use baking powder as a substitute for baking soda.