Strength of Acids and Bases

[Joana Fang 1K]

Why does a strong acid have a weak conjugate base and why does a strong base have a weak conjugate acid?

[Tess_Fleser_1D]

For the most part if the original acid or base is very strong, the result product would be close to neutral. A strong acid "really wants" a proton and a strong base "really wants" to give one up. Therefore the strong acid, now the conjugate base after the reaction, would be unlikely to then give up that acid, and the reverse with a strong base. The conjugate base formed by a strong acid is very weak because it is not likely to donate its proton (because as an acid it really wanted to get it), and the conjugate acid formed by a strong base is unlikely to accept a proton (because as a base it really wanted to get rid of it).

[305692127]

For something to be more acidic there needs tot be a higher KA and a lower pKA.

[kareena_prasad]

The stronger the acid, the weaker the conjugate base because the drive for the acid to be acidic is much higher than the drive for the base to be basic.

[Briana Chavez 3F]

Hi! Basically, strong acids very readily release their H+ ions. The conjugate base has no tendency to accept that released proton, which means that it is weak. Strong bases accept a proton and hold onto it, and there is no tendency for the conjugate acid to donate a proton, making it weak.

[205678283]

The conjugate acid complements a base just like a conjugate base complements an acid. You can think of them as a pair, so if one is weak, the other is strong (opposites attract)! When an acid loses its H+ ions, that is when it becomes the conjugate base. If an acid is really strong, it is much more effective as an acid than as a base, so its conjugate base will be weak.

[William Huang 1K]

A strong acid almost completely dissociates in solution or has a high Ka, meaning that for a strong acid HA + H2O, dissociating into H3O+ and A-, A- (conjugate base) would be a weak base because if Ka = [A-][H+]/[HA] and Ka is very high (numerator >denom), then H+ is not being converted back into HA like how a strong base would interact.

[Kimia Rategh 2A]

Hi! The way I think about it is that a strong acid is a really wanting to get rid of a proton and a strong base is one that is wanting to gain a proton. Therefore, when an acid, for example, gives up the proton it was so wanting to give up, why would it want to take a proton back. The resulting structure after an acid gives up its proton is relatively stable and with the negative charge and therefore is not very likely to take back another proton. This is why the conjugate base that results from the acid giving up its proton is called a weak base. A similar explanation can be used for bases and their weak conjugate acids. Hope this helps!