What happens when methane undergoes combustion in in systems A and B respectively? System A: Adiabatic container System…
Thermodynamics · Class 11 · JEE Main Previous Year Question
What happens when methane undergoes combustion in in systems A and B respectively? System A: Adiabatic container System B: Diathermic container
- a✓
System A: Temperature rises; System B: Temperature remains same
- b
System A: Temperature remains same; System B: Temperature rises
- c
System A: Temperature falls; System B: Temperature remains same
- d
System A: Temperature falls; System B: Temperature rises
System A: Temperature rises; System B: Temperature remains same
🧠 Adiabatic vs diathermic: who keeps the heat from combustion? Methane combustion is exothermic — it releases heat. Whether that heat stays in the system or escapes depends on the container type.
🗺️ Each system System A (adiabatic): No heat can leave. All heat released by combustion is trapped inside → temperature rises. ✓
System B (diathermic): Heat flows freely to the surroundings. The system stays in thermal equilibrium with the environment → temperature remains the same. ✓
Only option (a) matches: A rises, B stays the same.
⚠️ Trap: Students often think temperature rises in both systems. Diathermic just means heat can pass through the walls — the reaction happens, but the heat immediately escapes to the surroundings.
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