Baking soda (sodium bicarbonate) reacts with an acid in a chemical reaction. This creates carbon dioxide, a gas which produces air bubbles. The air bubbles make your pancakes puff up. In these pumpkin pancakes, baking powder make them rise and become fluffy. Baking powder is a combination of sodium bicarbonate and a powdered acid. When it comes into contact with moisture, the chemical reaction takes place. When you use baking powder, you don't need to worry about having a suitable acid in the recipe. The two necessary components are included in this one ingredient.