What is the reaction when salt is added to a cold drink?

When the salt gets dissolved by the soda, it changes the balance of the soda’s chemistry and forces the release of carbon dioxide bubbles from the solution. Essentially, thesalt “crowds out” the carbon dioxide and replaces it in the soda.

THE SALT REDUCES  THE FREEZING POINT OF THE WATER AND THIS ALLOWS THE ICE TO ATTAIN A TEMPERATURE LOWER THAN ZERO DEGREE CELSIUS

It reduces freezing point of the water

when salt is added to a cold drink like soda, the carbon dioxide gas bubbles clings onto the surface  of the  tiny salt crystals. As more carbon dioxide gas accumulates around the crystals, the gas becomes more buoyant. It then rushes out of the bottle forcing all the soda in its way to rise.