|MLA Citation:||Bloomfield, Louis A. "Question 982"|
How Everything Works 23 Jul 2018. 23 Jul 2018 <http://howeverythingworks.org/print1.php?QNum=982>.
However, molecule for molecule, calcium chloride will melt more ice than sodium chloride. That's because a single calcium chloride molecule decomposes into three separate ions in solution (one calcium ion and two chlorine ions). In contrast, a sodium chloride molecule only forms two separate ions in solution (one sodium ion and one chlorine ion). Since each ion contributes to the ice melting process, calcium chloride molecules are about 50% more effective than sodium chloride molecules. But even this increased molecular efficiency has a price: calcium ions are heavier than sodium ions, so a kilogram of sodium chloride actually yields more ions and more ice melting than a kilogram of calcium chloride. Still, salt is messy and corrosive so calcium chloride is often a good alternative.