When a recipe call for 2 teaspoon of baking soda how much Cream Tatar should you use?

Baking soda doesn't require or use cream of tartar as they play two different roles in baking. However, if a recipe calls for both baking soda and cream of tartar together that usually mean it is a baking powder substitute. In that case for every 2 teaspoon of baking soda, add 1 and 1/2 teaspoons of cream of tartar.