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
Mentor
"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 CO32-. 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
Gold Member
Maybe you should measure in moles per litre.
Or grams per litre.

"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 CO32-. 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