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Q & A: Baloney with salt and ice

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Most recent answer: 01/19/2011
Q:
http://wiki.answers.com/Q/How_efficiently_does_salt_melt_ice
Our second Baloney answer comes from a very popular wiki Q&A site. Such sites make little pretense of having reliable answers, so our criticism is kind of a cheap shot. Still, it seemed like a good idea to remind readers of how far off some of these open sites can often get. Question: "How efficiently does salt melt ice?"
- Mike W. (age 61)
A:
The main answer given is "....Salt doesn't melt ice. Instead, the properties of salt repel cold air and attract warmer air, seemingly melting the ice. ...."

Of course, as one can check by searching our site (try search terms "salt, freezing"), or reading any standard text on physical chemistry, salt does indeed lower the melting point of ice.  (An even better way to check is to sprinkle some salt on ice.) The primary reason is that the more liquid that forms, the greater the entropy of the salt dissolved in that liquid. This effect has nothing to do with imaginary effects of salt on air. It requires no air or any other complications.

Mike W.


(published on 01/19/2011)

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