Formula for the depression in freezing point is:
-(1)
where is depression in freezing point,
is Van't Hoff factor,
is molal freezing point depression constant, and
is molality of the solution.
Molality of the solution, (given)
Molal freezing point depression constant of water,
Depression in freezing point of solution,
Substituting the values in equation (1):
Hence, the Van't Hoff factor (i) for is 1.412.