Dissociation constant

In chemistry and biochemistry the dissociation constant, abbreviated K_d, is a measure of the extent to which a dissociation reaction

AB ↔ A + B

proceeds at equilibrium.

It is given quantitatively by the expression

K_d = [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