The Essence, Significance and Relationship of Polybasic Acid or Polybasic Base Titration Condition

The essence, significance and relationship of Polybasic Acid or Polybasic Base titration conditions were revealed with the titration curve. The findings showed that: K _i/K _i+1is the determining factor of stepwise titration and the primary indicator that influences the titration jump; while c _spiK _iis the key which determines the jump value when K _i/K _i+1is enough large. The decision procedure of before-titration is: first, to determine whether the K _i/K _i+1of the measured object is greater than or equal to 10 ⁵, so as to see whether the stepwise titration is applicable; then it is to determine whether c _spiK _iis greater than or equal to 10 ^-9, so as to see whether accurate titration can be directly applied under the current conditions.