Question

Why is the first dissociation constant larger than the second?

Answer 1

The smaller the dissociation constant, the more tightly bound the ligand is, or the higher the affinity between ligand and protein. For example, a ligand with a nanomolar (nM) dissociation constant binds more tightly to a particular protein than a ligand with a micromolar (μM) dissociation constant.

Answer 2

Explanation:

For polyprotic acids, the first Ka is always the largest, followed by the second, etc.; this indicates that the protons become successively less acidic as they are lost.