Question

Why do we have to break the test tube after heating Iron and Sulphur, i.e. forming the compound Iron Sulphide (FeS)???

Answer 1

Explanation:

For example, you can combine iron filings with sulfur to form a mixture. All it takes is a magnet to separate the iron from the sulfur. On the other hand, if you heat the iron and sulfur, you form iron sulfide, which is a compound; the iron and sulfur can no longer be separate from one another.