How does base strength vary for piperidine, pyridine, piperazine, and morpholine?
You want to order them in terms of basic strength?
Well, at a (hopefully informed!) guess, base strength should increase in the order:
Now we should be able to find
Now the higher the
And the order of reactivity in the carbonyls? Well you have got an aldehyde, versus 2 ketones. It is well-known that aldehydes are much more reactive than the corresponding ketones, by reason of steric hindrance and access to the carbonyl centre.