Are cola drinks decaffeinated naturally or with chemicals?

No cola drinks have caffeine removed, they have caffeine added. Unlike coffee, which naturally contains caffeine in its brewed beans, cola is just a mixture of water, corn syrup, phosphoric acid, flavoring and caffeine. So manufacturers just have to not add caffeine to their mixture to produce a caffeine-free version of cola. There's no decaffeination process drinks need to undergo.