2. Composition of Buffer Solution Buffer solution consist of weak acid and its conjugate base or weak base and its conjugate acid. The conjugate acid-base pair are called buffer system or buffer pair Important bufter pair such as HAC --AC NH4---- NH3 H2CO3-HCO3 HaPOA---- HPO H2PO4 --HPO4 HPO42-----POA32. Composition of Buffer Solution Buffer solution consist of weak acid and its conjugate base or weak base and its conjugate acid. The conjugate acid-base pair are called buffer system or buffer pair. Important buffer pair such as: HAc ---- Ac￾NH4 + ---- NH3 H2CO3 ---- HCO3 - H3PO4 ---- H2PO4 - H2PO4 - ---- HPO4 2- HPO4 2- ---- PO4 3-