Coca-Cola uses phosphoric acid. Here's a Coca-Cola bottling plant receiving a delivery of phosphoric acid.[1] It's marked with a 1805 (Phosphoric Acid, Corrosive, Class 8) placard. Of course, it's diluted as the product is mixed. This video shows the ingredients - tap water run through an de-ionizing plant, high fructose corn syrup in tank cars, phosphoric acid by the pallet load, flavoring (the "secret ingredient", in bags), and CO2 as a gas.

[1] https://youtu.be/7V6JO0Rfgas?t=189