Both baking soda and baking powder are leavening agents, which is a substance, used to produce fermentation in dough or batter. They are added to baking goods before cooking in order to cause them to ‘rise’. Although baking powder contains baking soda, both of these agents are used at different conditions.
Baking soda is pure sodium bicarbonate whereas baking powder contains sodium bicarbonate and other acidifying and drying agents such as cream of tartar and starch. When you use baking soda with moisture and other acidifying agents such as yogurt, chocolate, buttermilk and honey, it produces bubbles of carbon dioxide and cause baked goods to rise. When you add baking soda the reaction begins immediately after mixing the agents, therefore you need to bake the goods immediately or they will not provide effective results.
There are two types of baking powders available. One is single-acting baking powder, which is activated by moisture, so you must bake your goods immediately after mixing and the second is double-acting baking powder which reacts in two phases. Therefore it can last for a while before baking. Majority of the carbon dioxide is released after the temperature of the dough increases in the oven.
Summary:
Both baking soda and baking powder are used to produce fermentation
These agents can be added before cooking to cause baking goods to ‘rise’
Baking soda is made of pure sodium bicarbonate, while baking powder contains sodium bicarbonate and other agents.
When you add baking soda fermentation reaction starts immediately, therefore you should start the baking process immediately.
With baking powder majority of carbon dioxide is released once the temperature increases therefore you don’t need to bake your ingredients immediately.