Answer 1
OH (((-))) base
H3O (((+))) acid
+ = more acidic - = more basic
NH3 is 1- compared to NH4+ therefore NH3 is the base and NH4+ is the conjugate acid. The opposite is true for N2H(4/5)
Answer 2There is a very easy way to identify the parts of a Bronsted-Lowry acid/base reaction.
An acid is always a substance that donates a proton.
The conjugate acid also donates a proton, but in the OPPOSITE direction.
A base is always a proton acceptor.
The conjugate base accepts a proton, but in the OPPOSITE direction.
NH3 + N2H5+ <--> NH4+ + N2H4
base .. acid.......conj acid...conj base
The N2H5+ donates a proton and NH3 accepts it to make NH4+.
In the reverse reaction, NH4+ donates a proton and N2H4 accepts it in order to make the reactants. That makes NH4+ the conjugate acid and N2H4 the conjugate base.
======== Follow up ========
I think Ged would be better served by simply referring to the definitions of an acid and a base in the Bronsted-Lowry theory. It's much easier than this + vs - "explanation".
What about this reaction:
HSO4^- + H2O <==> H3O+ + SO4^2-
In this case the "negative" species is the acid, and the neutral compound is the base. That's just the reverse of Ged's suggestion.
But using the Bronsted-Lowry definitions of an acid and a base, we can easily see why HSO4- is the acid, because it donates a proton to water, which is the proton acceptor and therefore, the base.
In the reverse reaction H3O+ donates a proton, which makes it the conjugate acid, to SO4^2-, the conjugate base.
Wait a minute. I see where Ged is headed. He's saying that the + vs - constitutes the conjugate acid/base pair. According to his explanation, HSO4- is more positive than SO4^2- which makes HSO4- an acid and SO4^2- a conjugate base. And H2O is more negative than H3O+, which makes H2O the base and H3O+ the conjugate acid.
Ok. I get it. That works, too. It's not what Bronsted and Lowry had in mind, I'm sure, but it does work.
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