Close

09/08/2019

Which salt would be better to put on icy roads: NaCl or MgCl2? explain why?

QUESTION
Which salt would be better to put on icy roads: NaCl or MgCl2? explain why?
hi again, this is another question to be answered for a chemistry essay. if someone can answer this i would be very thankful.

ANSWER
From an economic point of view there’s simply no question: magnesium chloride costs about $180 per ton to produce while sodium chloride can be as little at $4. It could be 45 times less effective and still be the cheapest alternative! THAT is why about half the sodium chloride produced in the world is used to de-ice roads!

From a chemistry point of view, however, magnesium chloride probably does a better job of getting rid of ice. What you have to keep in mind is that since water is a polar solvent, the more polar stuff you have in there the happier it will be. Sodium chloride will give you one + and one -, but magnesium chloride gives you a 2+ and two -. Both MORE ions and STRONGER ones!

Curiously, this can also make magnesium chloride more reactive in other circumstances too. Though actual testing provides conflicting accounts, it has been suggested that magnesium chloride can be more corrosive and damaging to both metal and concrete than sodium chloride. Though that wasn’t really part of the question either.