. Iron filings and sulphur were mixed together and divided into two parts, ‘A’ and ‘B’. Part ‘A’ was

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 gases evolved


Best Answer

Part  A

Fe (s) + S (s)  FeS (s)

FeS + 2 HCl (aq) → FeCl2+ H2S

Part  B

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  + H2gas

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

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