posted by cs .
Which of the following is a conjugate acid-base pair?
A. H2SO4, H2SO3
B. NH3, NO2
C. CH3OH, CH3COOH
D. HF, H2F
E. NH3, NH4+
HA is an acid. A^- is the conjugate base BECAUSE A^- will add a hydrogen ion to become an acid.
Which of those pairs can you take away a H^+ to make the base (or add a H^+ to form the acid)?
Hint #1. Look at the last pair.
NH3, NH4^+. Note I can take a H^+ away from NH4^+ to form NH3. I can add a H^+ to NH3 to form NH4^+. So this is a base-conjugate acid pair. Can you do that with any of the others?