💏intro to chemistry review

Diprotic base

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

A diprotic base is a base that can accept two protons (H\(^+\)) per molecule. It typically undergoes two stages of protonation, each with its own equilibrium constant.

5 Must Know Facts For Your Next Test

  1. Diprotic bases have two distinct $K_b$ values, corresponding to each stage of protonation.
  2. The first $K_b$ value is always larger than the second $K_b$ value due to the decreasing availability of protons.
  3. Examples of diprotic bases include carbonate ion (CO$_3^{2-}$) and oxalate ion (C$_2$O$_4^{2-}$).
  4. In titrations involving diprotic bases, there are two equivalence points corresponding to each protonation step.
  5. The Henderson-Hasselbalch equation can be used for buffer calculations involving diprotic bases.
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