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?
Following reaction takes place when part A is heated:
Fe+S → FeS
When dil. Hydrochloric acid is added to iron sulphide, following reaction takes place and hydrogen sulphide gas is evolved.
FeS + 2HCI → FeCI2 + H2S
Hydrogen sulphide is a foul smelling gas and smells like rotten egg. When dil. Hydrochloric acid is added to the mixture of iron and Sulphur, following reaction takes place and hydrogen gas is evolved.
Fe + S → 2HCI → FeCI + H2 + S
In this case, Sulphur does not participate in the reaction.
When a burning matchstick is brought near the evolved gas the matchstick burns with a pop sound. This confirms the evolution of hydrogen gas.
