Assuming complete dissociation of the electrolytes, which of the following aqueous solutions will freeze at the lowest temperature?

Step-by-step solution

The depression in freezing point is given by T_f = i K_f m . Assuming molarity is approximately equal to molality for dilute aqueous solutions, T_f i C , where i is the van 't Hoff factor and C is the concentration. For 0.4 M Ethylene glycol: It is a non-electrolyte, so i = 1 . i C = 1 0.4 = 0.4 For 0.15 M CaCl ₂ : It dissociates into 3 ions ( Ca ²⁺ and 2 Cl ^- ), so i = 3 . i C = 3 0.15 = 0.45 For 0.1 M K ₄[ Fe ( CN )₆] : It dissociates into 5 ions ( 4 K ^+ and [ Fe ( CN )₆]⁴⁻ ), so i = 5 . i C = 5 0.1 = 0.5 For 0