[pisalko]

Which of the gases does not obey Henry's law upon dissolving in water: CO; SO₃; NO; NO₂; CH₄; NH₃; HCl ?
Justify your answer with chemical equations where appropriate.

/I do not understand a fragment of this because after all I've read on the subject it got even more confusing to me.../ Thanks in advance ! Also if you'd like explaining your answer would be awesome !

[Arkcon]

https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Physical_Properties_of_Matter/Solutions_and_Mixtures/Ideal_Solutions/Dissolving_Gases_In_Liquids%2C_Henry%27s_Law

There is a specific answer on that web page.  However, its not complete.  You may find other examples in your list that won't follow Henry's Law.