Colligative Properties

Question

Is this which salt would be better to de-ice a sidewalk NaCL or CaCl^2 and why ?

Answer 1

Either salt will LOWER the freezing point of water, but based on colligative properties, the one that provides the most number of particles will lower it the most.

1 mole NaCl ==> 1 mols Na⁺ + 1 mol Cl^- = 2 moles of particles

1 mole CaCl₂ ==> 1 mole Ca²⁺ + 2 mol Cl^- = 3 moles of particles

So, IF and ONLY IF they are present in the molar amounts, the CaCl2 will be a better de-icer than NaCl