I have used soda in cake mixes for 35 years. My favorite is strawberry soda with angel food cake mix. The cake comes out higher so there is "scraps" to nibble on.
Combine the cake mix and soda, then bake according to the cake mix baking instructions (do not add the additional ingredients on the box--just the soda).
The Best Scratch Cake Soda Recipes on Yummly | Made From Scratch Vanilla Cake, Banana Cake From Scratch - Old Family, Cherry Smashed Cake.