Baking powder, a leavening agent, is described as ‘double-acting’ due to its two-stage reaction process. First stage, when mixed with liquid, it releases carbon dioxide, forming bubbles that facilitate dough rising. Second stage when exposed to heat during baking, releasing additional gas to further aid in the expansion of baked goods. This double acting property ensures a consistent and controlled rise, making it suitable for recipes such as cakes, muffins, and quick breads.