Which solute, when added to 1,000 grams of water, will produce a solution with the highest freezing point?
(1) 0.5 mol of CaCrO4
(2) 1.0 mol of CaCrO4
(3) 0.5 mol of Na:CrO4
(4) 1.0 mol of Na:CrO4
Justify your answer: ​