[f1987]

I am studying for my exams at university and having problems writing a good answer for the attached question.  I am aware it is to do with electron withdrawing/donating groups effecting basicity but unsure what to write.
Any help welcome.

[Gregorian]

Think about it in terms of lones pairs and reasonance. In whcih compounds do the lone pair participate in the reasonance, and in which compounds they don't? When lone pairs do not participate in reasonance they can be used to abstract hydrogens (therefore they make the the compound more basic)
and also think about the withdrawing and donating effect of the substituent

[f1987]

So for Pyridazine; the N atom pulls electron density away from the Nitogen with the basic lone pair, this makes the lone pair less electron rich via a sigma effect.
2-methoxypyridine and 4-methoxyquinoline - both have an OMe group, need a little help here, i this more basic because this group is electron donating or is it because the O lone pair allows resonance to occur??
1 methoxy- 4- quinoline - lower basicity as the Me group causes steric hinderance, causing N lone pair to be less available and less basic.

[playstyles]

The lone pairs in the nitrogen compounds are not tied up in the resonance as their are in the heteroatoms of pyrol or furan. Therefore would they not be free to attack?