Question

Conjugate Acid and conjugate Base for the reaction NH3 + H2O _ Nh4+ + OH- is what?

Answer 1

Well look at defining reaction....

Explanation:

`"Acid + Base "rightleftharpoons" Conjugate base + conjugate acid"`

And so we got....

`underbrace(NH_3(aq))_"base" + H_2O(l) rightleftharpoonsunderbrace(NH_4^+)_"conjugate acid" + HO^(-)`

..or if we start with a ammonium salt...

`underbrace(NH_4^+)_"acid" + H_2O(l) rightleftharpoonsunderbrace(NH_3)_"conjugate base" + H_3O^(+)`

So the conjugate acid/base designation simply refers to proton transfer, i.e. plus or minus `H^+`....and as always, charge is balanced as well as mass.

Can you tell me the conjugate base of `NH_3`? This does not occur in aqueous solution, but it is conceived to occur in liquid ammonia. And what is the conjugate base of this species?

Going back to water, what is the conjugate base of hydroxide anion, `HO^-`? For quantitative considerations in water, see here.