The compound X2Y is only partially dissociated in water solution to form X and Y2- ions. A 0.0100 m solution is found to freeze at -0.040°C. Calculate the apparent percent dissociation of X2Y. Kf for water = 1.86°C/m.
i) 42%
ii) 56%
iii) 58%
iv) 79%
v) 85%