Which of the following is used as fuel in miners' lamp?

Correct answer: Ethyne (acetylene).

Explanation: Miners’ lamps historically used acetylene produced by reacting calcium carbide with water: \( \text{CaC}_2 + 2\text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_2 \,( \text{ethyne}) + \text{Ca(OH)}_2 \). Ethyne burns with a bright flame, making it suitable as a lamp fuel.

• Ethanal – an aldehyde, not used as a lamp fuel.
• Ethene – important feedstock for polymers, not a miners’ lamp fuel.
• Ethane – gaseous hydrocarbon, not used in traditional carbide lamps.