Click, Clack, and Jim have identical icy driveways. Click buys 10 lb of NaCl, Clack buys 10 lb of CaCl₂, and Jim buys 10 lb of MgCl₂. They spread these salts on their driveways. Which driveway will deice more effectively? (Assume that ideal dissociation of the salts occurs, and that colligative properties are the only consideration.) A)Click's driveway will deice best. B)Clack's driveway will deice best. C)Jim's driveway will deice best. D)The three driveways will deice to the same extent. E)Clack and Jim's driveways will deice better than Click's.

Question

Quizplus · Accepted Answer

MgCl₂ dissociates into three ions (Mg²⁺ and 2 Cl⁻), providing more particles than NaCl (2 ions) and CaCl₂ (3 ions), but MgCl₂ has a higher molar mass, so for the same weight, it provides more moles of ions, leading to a greater depression of the freezing point.

Click, Clack, and Jim Have Identical Icy Driveways