Bicarbonate of Soda or “ Baking Soda” is used in cooking as leavening, raising agent bread and cakes recipes that includes acidic ingredient such as lemon juice, yogurt, buttermilk or chocolate combined with moisture, to create air bubbles which cause food to rise when cooked.
Refer always to the specific amount in the recipe, adding extra bicarbonate can result in collapsed cake or strong unpleasant flavor