The carbonation in soda/soft drinks is a primary ingredient.This is carbon dioxide dissolved in water,this forms carbonic acid,which is a weak acid responsible for the tangy taste and also slight burning feeling when going down to your throat.Some sodas also have other acid added such as coca- cola which added ascorbic acid also adding flavour and burning taste.
Carbonation or fizz is the process of dissolving carbon dioxide in a liquid. The process usually involves carbon dioxide under high pressure. When the pressure is reduced, the carbon dioxide is released from the solution as small bubbles, which causes the solution to become fizzy.
Carbon dioxide is a harmless, odourless and colourless gas, which is present in the atmosphere and gives beverages a tangy taste and an invigorating drink sensation.