When can we ignore the contribution to the total H3O+ ion concentration from the dissociation of water?
(a) when KaCa < 1.0 x 10-13 (b) when KaCa = 1.0 x 10-13
(c) when KaCa > 1.0 x 10-13 (d) whenever we feel like it.
(e) when the cows come home.
Chemistry · Sun Jul 10 2022
Answered on
We can ignore the contribution to the total H3O+ ion concentration from the dissociation of water when the value of KaCa is smaller than a certain threshold.
To understand this concept, we need to first understand the concept of Ka (acid dissociation constant) and Ca (concentration of the acid). The Ka is a measure of how much an acid donates hydrogen ions (H+) in water. It represents the equilibrium constant for the reaction of the acid with water to form H3O+ ions. The Ca represents the concentration of the acid.
When the value of KaCa is very small (less than 1.0 x 10^-13), it means that the concentration of the acid is very low compared to the dissociation constant. In this case, the contribution of the acid to the total H3O+ concentration is negligible, and we can ignore it.
On the other hand, when the value of KaCa is larger than 1.0 x 10^-13, it means that the concentration of the acid is significant compared to the dissociation constant. In this case, the contribution of the acid to the total H3O+ concentration cannot be ignored and should be taken into account.
Therefore, the correct answer to the given question is (a) when KaCa < 1.0 x 10^-13.