Respuesta :

The reaction of baking soda or baking powder with the liquid in the batter: These ingredients react together and cause air bubbles to form. ... Heat of the oven: The heat of the oven can cause baking powder to react further and cause more air bubbles, and the heat also sets the structure of the cake.

Because baking soda reacts with the ingredients in cake resulting in trapped carbon dioxide, which give way to a rising batter due to heat. (honestly tres leches is my favorite type of cake)