[kevinklee2003]

So the rule for acidity, going from most important to least important is...CARDIO (Charge, Atom, Resonance, Inductive Effect, Orbitals).

But in the question below, which asks for the compound with the LOWEST pkB, and thus the most basic and least acidic compound, the order of importance between Resonance and Orbitals is switched.


Lone pairs/Electron delocalization DECREASE Acidity.
hybridization Increases Acidity in the following order: sp>sp2>sp3 from most acidic to least acidic.

The text im usingsays choice A is more basic than Choice D. But if we compare which is less acidic (and thus more basic), we see that
choice D has a resonance because of the elctrons in the double bond that can delocalize onto the nitrogen itself. So it has resonance which should DECREASE Acidity. However it is also, due to its double bond sp2 hybridized, which INCREASES acidity compared to choice A.

So choice D has Decreased acidity from Resonance and Increased acidity from its hybridization compared to Choice A. And since resonance trumps hybridiation in considerations of acidity, shouldnt choice D be the less acidic, and thus MORE Basic compound? But berkley only mentions hybridization? Do you just ignore electron delocalizatoin if you have a double bond?

[OrgXemProf]

1. You wrote: "Lone pairs/Electron delocalization DECREASE acidity". Are you referring to electron delocalization in the acid or in its conjugate base? Perhaps you can provide an example in this regard.

Can you apply a similar approach to decide which is the stronger base, pyridine or pyrrole?

2. Focus upon the relative basicity of A vs. D and then simply compare the hybridization of each nitrogen atom. Is it necessary to invoke resonance effects in order to evaluate the relative basicity of these two compounds?

3. You wrote: "The text I'm using says Choice A is more basic than Choice D".

Note that Choice A is a primary aliphatic amine, whereas Choice D (an imine) contains a pyridine-like nitrogen atom. Consider point #2, above to decide whether or not your textbook's statement is correct.
 

[mjc123]

Be careful what you are comparing. You write

But if we compare which is less acidic (and thus more basic)

This doesn't necessarily follow. Alkanes, for example, have extremely low acidity and basicity. The basicity of a compound is related to the acidity of the conjugate acid, not of the parent base. So if you want to compare the basicity of A and D, say, you should compare the acidity of AH⁺ and DH⁺, not the acidity of A and D.