[Sammy5124]

I keep finding the following claims:
1) Carbonic acid is an acid, so carbon dioxide is an acid since carbon dioxide forms carbonic acid (this ignores that only a small amount of carbon dioxide becomes carbonic acid at normal pressure; most of it still exists in co2 form)
2) Carbon dioxide is a base

I would think there would be a clear answer on something like this but it doesn't seem to be the case. Often claims such as "carbon dioxide dissolves limestone when dissolved in rainwater" are made. Is it the carbon dioxide dissolving the limestone, or is it carbonic acid?

[Archer]

What is an acid?

Can you define CO₂ as a Lewis acid or a Bronsted Lowery acid?

[Sammy5124]

So it's an acid because it fits the "Bronsted Lowery acid" definition of an acid", but does it actually dissolve limestone, or is that purely done by the carbonic acid?

[Archer]

So it's an acid because it fits the "Bronsted Lowery acid" definition of an acid", but does it actually dissolve limestone, or is that purely done by the carbonic acid?

Please would you provide your understanding of the definition of a Brønsted Lowry acid and show how this definition can be applied to CO₂

Are CrO₃ or SO₃ also Brønsted Lowry acids?

[Sammy5124]

I would say an acid is a molecule that can donate a hydrogen atom, I don't see how that can apply to CO2 as it has no hydrogen. That only leaves H2CO3 which has two hydrogen molecules

Yet I see the claim that carbon dioxide makes rain water acidic, I guess it's just a vague claim that is misinterpreted.

[Archer]

CO₂ + H₂O  H₂CO₃

Therefore CO₂ is not, by definition, an acid but when it i mixed with water it forms carbonic acid which is.

The same applies to sulphur trioxide and chromium trioxide, what acids do these form when mixed with water?

[antimatter101]

Firstly, you need to tell the difference between a Lewis acid, Bronst(o)d Lowry acid, and Arrhenius acid.