Numerous people find it difficult to distinguish baking powder and baking soda, but these two ingredients do not share the same chemical composition, so here is how to make the difference:
The reaction of baking soda or bicarbonate of soda or sodium bicarbonate with acidic ingredients releases carbon dioxide. When cooking, you need an acidic ingredient such as lemon juice, molasses, cream of tartar, yogurt, buttermilk, or brown sugar.
It is stronger than baking powder, and it gives a metallic taste if it is not neutralized. Note that you should add a quarter teaspoon of baking soda per every cup of flour.
Baking powder contains cornstarch, baking soda, and cream of tartar. When cooking, the first leavening occurs when the powder gets wet, and the other when it is heated. Also, make sure you add a teaspoon of it per every cup of flour.
Moreover, some recipes are much better if you use both of these, baking powder and baking soda, but you need to find the perfect balance since carbon dioxide from baking soda and acids might influence the volume after the leavening.
Also, baking soda and baking powder have expiration dates, so you should always use them fresh. Therefore, purchase new produce every three months, and test their power before use.
To do this, you should pour 3 tablespoons of white distilled vinegar in a small bowl, and add ½ teaspoon of baking soda. Stir well, and if the mixture floods with bubbles, the baking soda is fresh and good to use.