Is Measuring Bubbles a Reliable Method for Determining Carbonic Acid Levels?

[nibbel11]

Hello everyone

I am doing some research about carbonic acid in fizzy drinks. I hope to find out how much carbonic acid was in the drink by looking how much CO2 bubbles come loose. but later I thought that there are two reactions that can take place:

H2CO3 --> H2O + CO2
H2CO3 --> H+ + HCO3-

because both of these can take place does my plan still work, if not is there another way to find out how much is in the drink.

 

[Borek]

"How much carbonic acid" is a bit ambiguous, as it depends on what you mean by that.

Solutions contain dissolved CO₂ in equilibrium with H₂CO₂ (and the ratio between these two is rather difficult to measure, so we typically treat them as a single entity), plus - depending on pH - different amounts of HCO₃^- and CO₃^2-. To make things even more difficult, amount of CO₂ that the solution can release depends on the partial pressure of CO₂ in the atmosphere above.

Your definition of "how much carbonic acid" must take all these into account.

"Amount of bubbles lost by the drink" is a well defined (or rather - can be well defined, when you unambiguously describe how it is measured) property of a drink, so measuring it is a reasonable thing to do. Just don't call it "amount of carbonic acid".

 

[ISamson]

Maybe you should measure in moles per litre.
Or grams per litre.

 

[nibbel11]

"How much carbonic acid" is a bit ambiguous, as it depends on what you mean by that.

Solutions contain dissolved CO₂ in equilibrium with H₂CO₂ (and the ratio between these two is rather difficult to measure, so we typically treat them as a single entity), plus - depending on pH - different amounts of HCO₃^- and CO₃^2-. To make things even more difficult, amount of CO₂ that the solution can release depends on the partial pressure of CO₂ in the atmosphere above.

Your definition of "how much carbonic acid" must take all these into account.

"Amount of bubbles lost by the drink" is a well defined (or rather - can be well defined, when you unambiguously describe how it is measured) property of a drink, so measuring it is a reasonable thing to do. Just don't call it "amount of carbonic acid".

alright thank you