<prompt> The chief gas that is formed during decomposition is:H2SMethaneAmmoniaEthane  <response>: Ans. A.H2 SEffects of Gas formation In putrefactionHydrogen sulphide, CO2 , ammonia, methane, mercaptans.Gas bubbles cause crepitations.Postmortem purge - Oozing of blood from nostrils mouth.Gas stiffeningUterus anus prolapse.Face bloatingPm blisters 