Question

iron fillings and sulphur were mixed together and divided into two parts A and B part I was heated strongly while part B was not heated dilute hydrochloric acid was added to the both the parts and evolution of gas was seen in both the cases how will you identify the gases evolved

Answer 1

When iron mixed with sulphur and heated then it forms Ferrous sulphide (A) which on treatment with dilute HCl produces Ferrous chloride and Hydrogen sulphide gas. FeS + HCl →FeCl₂ + H₂S↑ If the mixture is not heated (B) remains as mixture (Fe + S) if it treated with dilute HCl then it produces Hydrogen gas along with Ferrous chloride . Since only iron reacts (Slowly) with HCl. (Fe + S) +2 HCl → FeCl₂ + H₂↑