Careful with your terminology, it is a deprotonation not a reduction. If you mean reduction in the sense of "decreasing concentration of", use "consuming" etc. - "reduction" is not a good word to use because it implies redox chemistry in this context.
Yeah, sorry, I meant "decreasing concentration of". I see how this would be a problem (it's just that I was typing at 3 AM!).
No, see AWK's post and again it is written here as well: http://en.wikipedia.org/wiki/Base_dissociation_constant#Bases
OK, so the clear choice for this case is NH
3 (aq) + H
2O
NH
4+ + OH
-. Meanwhile, if we describe this equilibrium I just wrote with the constant K
b, K
a for the action of the conjugate base NH
4+ is equal to K
w/K
b suggesting the reaction is NH
4+ + H
2O
H
3O
+ + NH
3.
My difficulty with Wikipedia's definition is: say we have an m-protic base B(OH)
m in solution - if it dissociates OH
- ions would that not itself make it a base? e.g. B(OH)
m B(OH)
m-1+ + OH- being Kb1, B(OH)
m-1+ B(OH)
m-22+ + OH
- being Kb2, etc. or am I writing the wrong reactions, because in these cases the conjugate acid forms are not being associated to protons? e.g. a concrete example: what are the two dissociations of Ca(OH)2? I would think the reactions were Ca(OH)
2 CaOH
+ + OH
- and CaOH
+ Ca
2+ + OH
- but there does not appear to be proton association here ...