Tertiary dissociation refers to the third step in the process of a weak acid or base dissociating in a solution. This step involves the removal of a third proton (H+) from the molecule.
Understanding Dissociation
Dissociation is the process where a compound breaks down into smaller components when dissolved in a solvent. For weak acids and bases, this process happens in stages, with each stage releasing a proton (H+).
Tertiary Dissociation in Acids
- Step 1: Primary Dissociation
- The acid molecule releases its first proton, forming a conjugate base.
- Example: HA ⇌ H+ + A-
- HA: The weak acid
- A-: The conjugate base
- Step 2: Secondary Dissociation
- The conjugate base releases another proton, forming a doubly charged conjugate base.
- Example: A- ⇌ H+ + A2-
- A-: The conjugate base from the primary dissociation
- A2-: The doubly charged conjugate base
- Step 3: Tertiary Dissociation
- The doubly charged conjugate base releases a third proton, forming a triply charged conjugate base.
- Example: A2- ⇌ H+ + A3-
- A2-: The doubly charged conjugate base from the secondary dissociation
- A3-: The triply charged conjugate base
Tertiary Dissociation in Bases
The process is similar for bases, but instead of releasing protons, they accept them.
Practical Insights
- Tertiary dissociation is typically much weaker than the primary and secondary dissociations.
- The extent of tertiary dissociation depends on the strength of the acid or base and the pH of the solution.
- Tertiary dissociation is important in understanding the behavior of complex acids and bases in solutions.
