date:Dec 21, 2018
does not need to be mixed with something acidic for it to work. Baking soda reacts immediately when it comes in contact with acid. Baking powder simply needs something liquid for it to react with and works more slowly than baking powder.
Sally's Baking Addiction explains the two are often combined in a recipe because the baked good needs more lift than baking soda alone can give it. Using baking soda alone can neutralize the acid in a food where you want the acid in ingredients to shine through