Question

Under what conditions vant hoff factor is equal to unity and less than 1 and greater than 1

Answer 1

i=1 When the solute does not undergo any dissociation or association in the solution i.e., for non-electrolyte solutes

i<1 Substance is in state of  association

Answer 2

The conditions under which vant hoff factor is unity, less than unit and greater than unity are as follow;--

When i=vantt hoff factor

a) When i=1 there is normal state of solute that is there is neither association nor dissociation of solute in the solution.

b) When i>1 there is dissociation of solute in the solution.

That is number of particles increases in solution hence observed mass is less than the normal molecular mass.

c) When i<1 there is association of solute in the solution.

That is number of particles decreases in the solution and observed molecular mass becomes higher than normal mass.

i=normal molecular mass/observed molecular mass

i= number of particles present in solution after dissociation or association/number of particles in solution before dissociation or association