That's not quite as reversible as I thought.
The balloon would increase in size, which would make the CO2 synthesis evident, but not quite serve as anything related to kinetics.
BUT! You can put soda in the cap, vinegar in the bottle, and close it as soon as possible. You'd feel the inner pressure increase. You could open it a bit, and the CO2 would escape. After that, inner pressure would decrease. There could be still CO2 trapped in the solution, or soda that didn't react because there was no space for the to-be-produced-CO2. Since you freed some, there is space for some more to react.
The aforementioned method works in my head. I don't know if a cap stores enough soda to maximize the pressure, and still enough to react once you let some escape. You could try a method that drops more vinegar than what fits in a cap.