<prompt> Pin index system for oxygen1,52,54,53,5  <response>: Ans: b 2,5Ref: Millers Anaesthesia 7th ed. 675 Pin index for oxygen is 2, 5. Cylinder of oxygen is black body with white shoulder.GasColor CodePin index positionBodyShoulderOxygenBlackWhite2,5Nitrous oxideBlueBlue3, 5CO2GrayGray1,6HeliumBrownBrown2,5AirGreyWhiteblack quartered1,5 