Why can you substitute baking powder for soda in quick breads but not powder?

Baking powder can be used in place of baking soda in yeast breads because the acid component of baking powder reacts with the baking soda to produce carbon dioxide gas, which is the leavening agent that makes the bread rise. However, baking powder cannot be used in place of baking soda in baked products made with quick breads, such as pancakes and waffles, because baking powder does not produce gas until the liquid ingredients in the batter are combined with the dry ingredients. If baking powder was used instead of baking soda in a quick bread, then the batter would not have time to rise properly before the bread is cooked.