[CNR-engineering]

  Which of the following acids would have the strongest conjugate base?

A. HOCl       Ka= 2.9 x 10^-8
B. HOBr       Ka= 2.4 x 10^-9
C. HOI         Ka= 2.3 x 10^-11
D. H2O2      Ka= 2.2 x 10^-12
E. H20         Ka= 1.8 x 10^-16

I know the lower the value of Ka the weaker the acid which would give you a stronger conjugate base, but Is H20 and H202 conisdered an acid?

[Borek]

Can be treated this way.

[CNR-engineering]

So by that im assuming  you mean it can be which would make the anwser H20 correct?

[Arkcon]

Yes, water is a stronger base than say, hypochlorous acid, that's why water can pull the proton off HOCl, which is why we call HOCl -- hypochlorous acid. 

I'll admit 'tho, that water is a stronger base than hydrogen peroxide leaves me a little bit confused, does H₂O₂ really lose a proton in aqueous solution?  The numbers are there in your question, but the concept is a little far out for me.  So I do understand your confusion.

[AWK]

Yes, water is a stronger base than say

OH^- is the  strongest conjugated base