Baking soda and acid cause the same reaction as baking powder does, resulting in a quick rise. To use it in place of yeast, use 50% baking soda and 50% acid as a one-to-one replacement.
Good rule of thumb: I usually use around 1/4 teaspoon of baking soda per 1 cup of flour in a recipe. Baking soda CAN leaven a baked good when exposed to heat. However, unless it is neutralized with an acid, your finished baked good will likely have a metallic aftertaste– like I mention above.