Iron filings and sulphur were mixed together and divided into two parts, 'A' and 'B'. Part 'A' was heated strongly while part 'B' was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gasesevolved?

Iron filings and sulphur were mixed together and divided into two part

1.	Iron filings and sulphur were mixed together and divided into two parts, 'A' and 'B'. Part 'A' was heated strongly while part 'B' was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gasesevolved?
Answer» Solution :(i) In part 'A' iron and sulphur will remain as such in the form of mixture. On adding dilute hydrochloric ACID, iron will react to evolve hydrogen gas. The gas can be tested by bringing a burning splinter near its mouth. It will burn with a pop sound. `Fe(s) + 2HCl(aq) rarrFeCl_(2) (aq) + H_(2)(g)` (ii) In part 'B' iron sulphur will combine on heating to form greyish black SOLID known as iron sulphide `Fe(s) + S(s) overset("heat")rarrFeS(s)` When dilute hydrocloric acid is added to the greyish black MASS taken in a TUBE, a gas with foul smell SIMILAR to that of the rotten eggs will evolve. This is hydrogen sulphide `(H_(2)S)` `FeS(s) + 2HCl(aq) rarr FeCl(aq) + H S (g)`