What is a conjugate acid of #OH^-#?
Well what do you get when you add a proton to the beast?
And thus the conjugate acid of hydroxide ion is simply water.... And for the conjugate base we remove a proton, and for the conjugate acid we ADD a proton. And mass and charge are as always CONSERVED.
And what is the conjugate acid of water?
What is the conjugate base of hydroxide? And the conjugate base of ammonia,