Why does the pH value of a carbonated liquid is higher than when it's decarbonated?

Question

A carbonated tonic drink has the pH value of 2.45 but this will be reduced when it's decarbonated. Why does this happen?

Answer 1

Are you sure you don't have that turned around? The pH value should increase (become a higher number) with when the carbon dioxide is removed. When the concentration of hydronium ions (the amount of acid present) decreases, the pH will increase in value. Pure water with no carbonation should have a pH of about 7 (higher than 2.45). The key to understanding why carbonated water has a lower pH is finding out what is produced when carbon dioxide reacts with water (see the source links).