In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl2 solution is _____________.
Depression in freezing point = i × m × Kf
Now, i = van’t Hoff factor, m is the molality and Kf is the freezing constant of the solvent.
Here, we see that molality is the same i.e. 0.01 M and Kf will be the same as the solvent is water.
Thus, depression in freezing point depends only on the van’t Hoff factor.
i = Total number of ions after dissociation/association/Total number of ions before dissociation/association.
i= 3 for MgCl2 as it dissociates into 3 ions
i = 1 for glucose as it does not undergo any association/dissociation.
Thus, option (iii) is the correct option.