Q & A: If you use cocoa powder instead of flour, it is necessary to add baking soda for some reason?

question Jetta : When using cocoa powder instead of flour only, it is necessary to add the baking soda, for a reason comparison a pound cake recipe for chocolate cake book. A regular cake mix 3 cups flour, replaced chocolate recipe cocoa 3/4 cup baking soda, and – it’s a necessity? The point of the cocoa too heavy best answer is (or heavier than flour?): Response