Define van't Hoff factor . What is its importance? How does it account for abnormal molecular masses?

Explanation

Van.t Hoff Factor. If may be defined as the ratio of the observed values of the colligative property to the theoretical value of colligative property .i.e.
` i = (" Observed value of colligative property ")/( " Theoretical value of colligative property ") `
Since colligative properties are inversely proportional to molecular mass of the solute, it follows that
`i = (" Normal or calculated molecular mass")/(" Observed molecular mass") `
When certain solute either undergoes association or dissociation, the number of particles in solution either decreases or increase. In such case ` i ne 1` and molecular masses calculated by using any colligative property is different or abnormal
Importance. The factor expresses the extent of association or dissociation which a certain solute undergo is solution
If (i) `i gt 1 ` there is dissociation of solute particle
(ii) `i lt 1 ` there is association of solution particles.