उत्तर : 2. "कैल्शियम"
व्याख्या :

1. Which of the following calcium elements is not a component of baking soda?

2. The chemical formula of baking soda is NaHCO3, which is composed of four elements sodium, hydrogen, carbon and oxygen.

3. Baking soda is an alkaline substance used as a leavening agent in baking.