Soda is actually just a cold drink. It contains carbon dioxide, with proper amount of sugar, citric acid, essence, food pigment and so on. If carbon dioxide of about 2 ~ 3 atmospheres is sealed in sugar water, a part of carbon dioxide gas will dissolve in water, and carbon dioxide will form carbonic acid in water. The pungent taste of soda water is due to carbonic acid.
reference data
Baidu encyclopedia. Baidu Encyclopedia [reference time 20 18-4-3]