<prompt> Gas cylinder with single pin index -OxygenAirNitrogenEntonox  <response>: Ans. is d i.e., Entonox GasPin indexOxygen2,5Nitrous oxide3,5Cyclopropane3,6Air1,5Nitrogen1,4Entonox 50 O2 50 N2OSingle central 7Carbon dioxide 7?52,6Carbon dioxide 7?51,6 