It all comes down to chemistry, baby! Baking soda (sodium bicarbonate) is a base that needs an acid, like buttermilk or yogurt, to activate it. Baking powder, on the other hand, is a mixture of baking soda and an acid (usually cream of tartar) that's designed to release gas more slowly over time.
So, if you substitute baking powder for baking soda, you'll end up with a different reaction. It's like trying to put diesel fuel in a gasoline-powered car – it just won't run smoothly, and you might end up with a cake-astrophe on your hands.
But here's the thing: in some recipes, you can use baking powder as a substitute for baking soda, but you'll need to use more of it. Like, a lot more. We're talking three times the amount of baking powder as baking soda. That's a whole lotta powder, if you know what I mean.
Is Baking Soda Baking Powder The Same Thing | Naked Grapefruit