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Dissociation constant - Definition and Overview |
| Related Words: Atomization, Autism, Bombardment, Breeding, Bullet, Catalysis, Catalyst, Cleavage, Compensation, Decay, Decompensation, Depersonalization, Dialysis |
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In chemistry and biochemistry the dissociation constant, abbreviated Kd, is a measure of the extent to which a dissociation reaction
- AB ↔ A + B
proceeds at equilibrium.
It is given quantitatively by the expression
- Kd = [A]×[B]×[AB]-1
Where [A], [B], and [AB] indicate the concentrations of A, B, and AB, respectively.
See also hydrogen bond.
The dissociation constant is a specific type of equilibrium constant.
The dissociation constant of water (Ke) varies in function of the temperature. The value of pH for neutrality is not the same at different temperatures.
| water |
Ke |
pKe |
| 0°C |
0.1e-14 |
14.92 |
| 10°C |
0.3 |
14.52 |
| 18°C |
0.7 |
14.16 |
| 25°C |
1.2 |
13.92 |
| 30°C |
1.8 |
13.75 |
| 50°C |
8 |
13.10 |
60°C |
12.6 |
12.90 |
| 70°C |
21.2 |
12.67 |
| 80°C |
35 |
12.46 |
| 90°C |
53 |
12.28 |
| 100°C |
73 |
12.14 |
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