Making chocolate chip cookies without baking soda is possible if it is replaced with another ingredient, such as baking powder. As both of these ingredients are leavening agents, they are compatible substitutes for each other.
The substitution equivalents are that half a teaspoon of baking soda is equal to 2 teaspoons of double-acting baking powder. However, any acidic liquids in the recipe need to be replaced with non-acidic ones.
In baked goods such as chocolate chip cookies, these leavening ingredients cause batters to rise. Baking soda or sodium bicarbonate is a base that acts as a neutralizer in recipes that have acidic ingredients, such as chocolate or buttermilk. Baking powder consists of sodium bicarbonate and acids such as monocalcium phosphate and sodium aluminum sulfate. For this reason, there also has to be a replacement of any acidic liquids when substituting baking powder for baking soda.