What is the difference between TIC and alkalinity?

[TvEp]

Hey there,

What is the difference between Total Inorganic Carbon (TIC) content and alkalinity?

When I am reading it says that the TIC consists of:
- H2CO3 / aquous CO2
- HCO3-
- CO32-

And it says that alkalinity consists of all acid-neutralizing compounds, portayed as CaCO3, but consisting of:
- HCO3-
- CO3 2-

Does that mean that the only difference is that the TIC also consists of H2CO3 / CO2 concentration, whereas alkalinity only consists of HCO3- and CO32-.

Are there any other acid-neutralizing components that could add to alkalinity that I am missing?

 

[symbolipoint]

Not everybody takes the convention for alkalinity equivalent to CaCO₃. Some people expect and use alkalinity equivalent to Na₂O.

 

[TvEp]

Thanks. What does that mean concretely for what you are exactly measuring? Does it not remain to be all acid-neutralizing components? So HCO3-, CO3 2- and OH-?

 

[symbolipoint]

Thanks. What does that mean concretely for what you are exactly measuring? Does it not remain to be all acid-neutralizing components? So HCO3-, CO3 2- and OH-?

I feel sure about the meaning of Total Inorganic Carbon, but I will avoid saying what this is, exactly. But for the meaning of alkalinity, if you are in a community or group which uses this to mean, "equivalents to sodium oxide", then this would be linked to what one would find if to do a neutralization titration. Something alkaline may be measured and then dissolved in water. An acid titrant is used to neutralize to some desired endpoint, and the number of moles of Hydronium ions can be computed. Then, the amount of Na₂O which was titrated can also be computed.

Many compounds may be alkaline and can be neutralized with an acid titrant. Example, Na₃PO₄. Dissolved in water, the solution takes on a pH higher than 7. Not the same as Na₂O, but that does not matter. Take a measured sample, titrate, and just assume you neutralized Na₂O.