The Conjugate Seesaw

[905085650]

Can someone explain the conjugate seesaw to me? Thank you!!

[amogha_koka3I]

I had a similar question and found a post on chemistry community for it:
viewtopic.php?t=8560
Hope it helps!

[Eunice Lee 1A]

The conjugate seesaw states that the stronger the acid, the weaker its conjugate base. The stronger the base, the weaker its conjugate acid.

[caseygilles 1E]

The conjugate seesaw says that the stronger the acid, the weaker that acid's conjugate base. The stronger the base, the weaker that base's conjugate acid. But here's why... We know that Ka * Kb =Kw, and we know that Kw is a the ionization constant of water= 1* 10^-14. Therefore if we have a large Ka, meaning that we have a strong base that dissociates a lot or even completely, then Kb must be small because Ka times Kb is a constant (1*10^-14). The same logic holds with a strong base.

[Karina Jiayu Xu 4E]

Because Ka and Kb have inverse relationships since Kw is a constant

[Jonathan Pai 2I]

Ka*Kb = Kw

Kw is always 1.0x10^-14, so is one value increases, the other decreases.

[MadelineHlobik]

Does Kw=Ka*Kb and Kw=[H3O][OH]

[Jessica Chen 1F]

An example of the conjugate seesaw could be NaOH.
NaOH is a strong base, but its conjugate acid, Na+, is so weak that it's basically a neutral cation and won't affect the pH of the solution.

[Simran Rai 4E]

Does Kw=Ka*Kb and Kw=[H3O][OH]

Yes, so since Kw = 10^-14, [H30+] has to be 10^-7 and [OH-] has to be 10^-7 as well.

[Chris Dis3L]

The conjugate seesaw describes the relationship between conjugate acids and bases. A strong acid has a weak conjugate base. Similarly, a strong base has a weak conjugate acid.

[Kaylee Kang 1G]

Kw is always constant, and Ka*Kb=Kw, so if Ka increases, Kb decreases, and vice versa.

[Laurence Tacderas 1K]

Since Kw is a constant value, the strengths of acids and their conjugate bases (as well as bases and their conjugate acids) are complimentary. That would make sense if you think about it: the stronger an acid/base, the more likely it will stay disassociated and thus its conjugate base will be weaker and less likely to go back to the reactant form.

[JT Wechsler 2B]

Basically, if there is an acid base reaction, the base (on the reactants side) will have a conjugate acid (on the products side), and vice versa. Since this is the case, it may be necessary to convert Ka to Kb (or the other way around) depending on what way you are looking at the reaction.

[George Ghaly 2L]

In very simple terms the conjugate seesaw basically states that the stronger the base or acid is, the weaker its conjugate acid or base is.