Q. Which among the following gas has lowest auto-ignition temperature?
Answer: Carbon Di Sulphide
Notes: The auto-ignition temperature of a liquid, gas or vapor is the temperature at which the substance will ignite without any external heat source. Here is the temperature of some gases: 
Methane -580 °C 
Hydrogen -560 °C 
Propane -493 °C 
Ethylene -425 °C 
Acetylene -305 °C 
Naphtha -290 °C 
Carbon disulfide -102 °C

This question is part of 40000+ General Studies MCQ Series Course on GKToday Android app. Question Number: 13 in Chemistry-15-Hydrocarbons & Fuels in above course in App.