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Chemistry / Nails rusting in salt solution, white crystals
« on: 03/02/2014 12:23:59 »
My students do a familiar experiment, observing the rusting of iron nails in salt solution in test tubes. The expected reaction products, orange rust, black magnetite, and green/blue ferrous hydroxide (top to bottom), are usually described.
Consistently occasional students report that some white crystals are seen at the bottom of the tube (but I have not seen them). My only guess is that they are hydrated ferrous chloride precipitate, actually light green but looking white in contrast with the black oxides.
Does anyone know what these crystals are?
Consistently occasional students report that some white crystals are seen at the bottom of the tube (but I have not seen them). My only guess is that they are hydrated ferrous chloride precipitate, actually light green but looking white in contrast with the black oxides.
Does anyone know what these crystals are?