Nitrous oxide (N2O), one of several oxides of nitrogen, a colourless gas with pleasant, sweetish odour and taste, which when inhaled produces insensibility to pain preceded by mild hysteria, sometimes laughter. (Because inhalation of small amounts provides a brief euphoric effect and nitrous oxide is not illegal to possess, the substance has been used as a recreational drugs. NO2 Uses (Nitrogen dioxide) Nitrogen dioxide is used as an intermediate in the production of nitric acid. Used in the manufacturing of oxidized cellulose compounds. Used as a catalyst. Used as an intermediate in the production of sulphuric acid. Used as an oxidizer for rocket fuels. Used as a nitrating agent.