Iron fillings 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?

AcademicChemistryNCERTClass 9

When iron fillings and sulphur is heated it will give the following reaction:
$Fe(s)+S(s) → FeS$

When HCl is added to this mixture Ferric chloride is produced and Hydrogen sulphide gas is produced. A foul rotten egg smell of Hydrogen sulphide is the indicator of H2S production.
$FeS + 2HCl \rightarrow FeCl_2 + H_2S$

When dilute HCl is added to this setup B, Hydrogen gas is evolved and sulphur does not take part in the reaction. When a burning matchstick is brought near the evolved gas, the matchstick burns with a pop. This is the indication of the production of Hydrogen gas.
$Fe + 2HCl \rightarrow FeCl_2 + H_2$
Updated on 10-Oct-2022 13:29:39