Fe (s) + S (s) Heat FeS (s)
FeS + 2 HCl (aq) → FeCl2 + H2 S
Fe (s) + S (s)→ Mixture of iron filings and sulphur
When dilute HCl is added to it
Fe (s) + S (s) + 2 HCl (aq) → FeCl2 + H2 gas
Sulphur remains unreacted
H2S gas formed has a foul smell and on passing through lead acetate solution, it turns the solution black. Hydrogen gas burns with a pop sound.