Question

Which of the following represent conjugate acid-base pairs? For those pairs that are not conjugates, write the correct conjugate acid or base for each species in the pair.
a. HS-4-,SO4^2-
B. HBr, BrO-
c. H2PO4-, PO4^3-
d. HNO3, NO2-

Answer 1

You can do these yourself if you follow one rule.
The acid of the "pair" has an extra H. The base of the "pair" has one fewer H.

So look at the first one. The "pair" would be HSO4^-/SO4^2-
B would be HBrO/BrO^-
C is H2PO4^-/PO4^3-
I'll leave D for you.

Answer 2

D is not conjugate pairs , because the anion part of the acid ( NO3 - of HNO3 ) differs from the NO2-