Question

Formula relation between degree of dissociation and degree of association

Answer 1

Degree of association, van't Hoff factor and dissociation constant. Where α is the degree of dissociation. Therefore, i=1−α+α+α=1+α, and α=(i−1).

Answer 2

Following Wikipedia's van 't Hoff factor discussion, the van 't Hoff factor can be computed from the degree of ionization as follows

i = αn + (1 - α)

where α is the degree of dissociation and n equals the number of ions formed from one formula unit of the substance. The formula above is often rearranged as follows:

i = 1 + α(n - 1)

The form just above is what I will use in the solutions below.

Example #1: What is the expected van 't Hoff factor for a substance (such as glucose) that does not ionize at all in solution.

Solution:

α = 0

n = 1

i = 1 + 0(1 - 1)

i = 1                                                                                                                              Degree of association, van't Hoff factor and dissociation constant. Where α is the degree of dissociation. Therefore, i=1−α+α+α=1+α, and α=(i−1).