What Is Nitrous Oxide or Laughing Gas?Nitrous oxide (N2O) is also known as laughing gas. It is a colorless sweet-smelling and sweet-tasting gas that is used in dentistry and surgery because inhaling the gas produces analgesic and anesthetic effects. The gas is also used to produce the engine output of automotive vehicles and as an oxidizer in rocketry. Nitrous oxide gets the name "laughing gas" because inhaling it produces euphoria.
How to Make Nitrous Oxide or Laughing GasJoseph Priestley first synthesized nitrous oxide in 1772 by collecting the gas produced from sprinkling nitric acid over iron filings, however, nitrous oxide usually is produced using Humphry Davy's method of gently heating ammonium nitrate to decompose it into nitrous oxide and water vapor:
NH4NO3 (s) → 2 H2O (g) + N2O (g)
The key here is gently heating the ammonium nitrate to between 170°C and 240°C, because higher temperatures may cause the ammonium nitrate to detonate. People have been doing this without incident for over 150 years, so they key is to be careful. Next, the hot gases are cooled to condense the water. The best way to do this is using a pneumatic trough, which involves a tube leading from the ammonium nitrate container that bubbles the gases up through water into a collection jar. This removes the water from the reaction as well as smoke from impurities in the ammonium nitrate. The gas in the collection jar is your nitrous oxide or laughing gas, plus lesser amounts of other nitrogen oxides, including nitric oxide or nitrogen monoxide. Nitric oxide is oxidized to nitrous oxide upon exposure to oxygen, although acid and base treatments are used to remove impurities for commercial-scale production of nitrous oxide.