Baking Powder Reacts With Any Liquid Baking powder's acidic component, cream of tartar, is built in and reacts with the included alkaline baking soda when it comes in contact with any liquid.

Baking powder is a combination of a powdered alkali ... It’s the imbalance in the ratio of the alkali and acid components that can give a finished recipe a bitter chalky flavour.

whereas baking powder already contains an acidic component. Single-acting powder - This type contains only one acid, usually cream of tartar, and it reacts with moisture as soon as it is mixed ...