Question

It a centimolal aqueous solution of K₃[Fe(CN)₆] has degree of dissociation 0.78. What is the value of van't Hoff factor?

Options

• 1.2

• 4.0

• 3.34

• 2.5

Answer 1

3.34

Explanation:

Given,

Degree of dissociation (α) = 0.78

\[\ce{K3[Fe(CN)6] -> 3K^+ + [Fe(CN)6]^3-}\]

That means, total moles formed after dissociation (n) = 4

We know that,

van't Hoff factor (i) = αn + (1 − α)

= 0.78 × 4 + (1 − 0.78)

= 3.122 + 0.22

= 3.34