Dilute hydrochloric acid was added to both the Parts and evolution of gas

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? 

Answer: Hydrogen gas is released, when dilute hydrochloric acid is added to part ‘A’. Hydrogen gas can be tested by brining a burning matchstick or candle

near it. 

When a burning matchstick is placed near the hydrogen gas, it burns with a pop sound, which is a test for hydrogen gas. Hydrogen sulphide gas released when dilute hydrochloric acid was added to part ‘B’. 

Hydrgoen sulphide gas smells like a rotten egg, hence it could be confirmed by its smell.