[hameeda]

What happens in the reaction of heating iron and sulpher togather??

[CliffARobinson]

On heating the reaction mixture, the sulfur melts and reacts with the iron exothermically to form iron(II) sulfide. The mineral wool plug in the mouth of the test-tube prevents sulfur vapour escaping and possibly catching fire. If, despite all precautions, the sulfur vapour does ignite, students must be trained to extinguish it by placing a damp rag firmly over the mouth of the tube.

The signs that a chemical reaction occurs are: the glow, and the fact that a new substance (black iron sulfide) is formed which cannot be separated by using a magnet.

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