KNO2 Dissolution

[Edward OKeefe IV]

If KNO2 is dissolved in a solution, it would act as a weak base as the cation is a component of strong bases and the anion forms only weak acids, but if we isolate the K+, does it behave as a conjugate acid to the base of K(OH)? If so, how strong is it as an acid?

[Ella Henrickson 3I]

For K+, it comes from the strong base KOH and so it has a negligible effect on the pH of a solution. That means that for whatever problem you are working on with KNO2, NO2- would be acting as a weak base since it comes from HNO2 which is a weak acid and K+ wouldn't have an effect on the pH.

[Stephen_Kim_1D]

but if we isolate the K+, does it behave as a conjugate acid to the base of K(OH)? If so, how strong is it as an acid?

The reason we "ignore" the K+ when KNO2 is dissolved is that it's the "conjugate acid" to the strong base KOH. I put "conjugate acid" in quotations because it doesn't actually act as an acid. Instead of adding KNO2, imagine instead that we put KOH in water. By the definition of a strong base, this fully dissociates into K+ and OH-. In other words, there's OH- floating around making the solution basic and K+ that won't go back to KOH. Similarly, in a KNO2 solution, you have K+ ions floating around that won't accept any OH-. That's why the K+ is ignored since it doesn't affect the solution (and since it doesn't accept OH-, it doesn't act like an acid).

[Benjamin Nguyen 1J]

Since KOH is a strong base, K+ wouldn't act as a conjugate acid since the reverse reaction back to KOH doesn't happen.