Nitrous Oxide (N2O) is most known for its recreational and anesthetic purposes. It causes amusement on inhaling some of it, which is why it’s also famous as the laughing gas.
Nitrous Oxide (N2O) is a colorless and nearly odorless gas. It is also known by other names such as nitrogen oxide, dinitrogen monoxide, hyponitrous acid anhydride and factitious air. However, the gas is popularly known all over the world as ‘the laughing gas’, for its provision of amusing effects to whomsoever inhales it.
The credit of discovering the nitrous oxide goes to an English scientist and clergy man Joseph Priestley, when he did so in the year 1772. By then, Priestley had garnered quite a reputation, as he was also the first person to isolate and discover other important gases such as oxygen, carbon monoxide, carbon dioxide, ammonia, and sulfur dioxide. He discovered nitrous oxide while he was ammonium nitrate in the presence of iron filings. He passed the emitted gas through water for eliminating toxic and other unnecessary by-products. However, the reaction that he observed instead was:
2NO + H2O + Fe → N2O + Fe(OH)2
At first, Priestly thought that the discovered gas could be used as a preserving agent, but all his attempts to do so proved to be futile. However, what Priestley didn’t know was that his discovery was soon going to be used as a recreational agent. A certain Humphry Davy of the Pneumatic Institute in Bristol, England, conducted various experiments with the gas to determine its physical properties and effects upon inhaling it. For this purpose, Davy even administered the gas to his visitors. Upon inhaling small amounts of the gas, there seemed to be an amusing effect on the inhaler for some time, until the gas’ influence wore off eventually. Experiments like these, led Davy to coin a new term for this gas, which was ‘the laughing gas’.
Following this famous experiment and the popularity of nitrous oxide as ‘the laughing gas’, N2O was being primarily used for recreational purposes at public shows and carnivals. There were many traveling medicine shows which were themed on the laughing gas as well. The gas went on to become such a rage that people were even willing to pay for inhaling a minute’s worth of nitrous oxide. The people would inhale the gas, laugh, act silly, enjoy the good time, and stand about in utter confusion as the effect of the gas gradually wore off. The gas turned Davy into a celebrity of sorts, who was frequented by many high profile guests for a little puff of his purified laughing gas.
After the gas became hugely popular and widely available for the public, many scientists and researchers began to conduct their own experiments and exhibitions of the gas. One such gentleman was Gardner Quincy Colton, a medical school dropout, who went around the length and breadth of England with his N2O exhibitions. One of his exhibitions was graced by a local dentist named Horace Wells. Wells was curious to know the effects of the gas, once it was administered to a volunteer from the crowd. As expected, Colton asked for a volunteer and a man named Samuel Cooley volunteered for the same.
As usual, the gas seemed to affect Cooley in an amusing manner, and he began to act silly. He even staggered into some benches placed nearby and injured his leg. However, Cooley appeared to be unaware of his injuries till the effect of the gas wore off him. This made Wells immediately realize that the gas may also provide some analgesic qualities to its inhaler, along with the usual recreational ones. Wells decided to conduct an experiment to ratify his notion of the gas, and invited Colton for the same. Next day, Colton arrived with the gas and administered it to Wells, while he was having one of his molars extracted from another dentist. The conclusion was that Wells experienced no pain and nitrous oxide came to be known as a medicinal anesthetic as well.
Unfortunately though, it took an act of suicide by Dr. Wells for nitrous oxide to be officially accepted as an anesthetic substance and Wells himself as the "Discoverer of Anesthesia". The story goes that Wells was once demonstrating the anesthetic effects of the gas on a patient at the Harvard Medical School in Boston, USA. The patient had been anesthetized before going ahead with the dental procedures of extracting his tooth. The experiment was successful, but the patient claimed of some pain during the same. Although the patient only felt some discomfort and not any unbearable pain, Dr. Wells was infamously booed off the stage. The event led to Wells losing his status of being a professional dentist, and eventually committing suicide three years later. The gas is till today being used by dentists all over the world, as it is less toxic than chloroform, way less explosive than ether, and offers some painkilling ability to the patients as well.
Apart from its uses as a recreational agent, an analgesic and an anesthetic substance, N2O is also famous for providing incredible acceleration to race cars, etc. The use of N2O has been widely depicted in racing based movies such as The Fast and the Furious and games such as Need for Speed. The reason for such a use of nitrous oxide is because it’s an excellent propellant.
Nitrous oxide is fairly unreactive with many substances such as alkali metals, halogens, and even ozone at room temperature. However, when it is heated effectively, N2O breaks into N2 and O2 . This exothermic reaction can be represented by:
This reaction is the basic reason for why nitrous oxide is used as a propellant in aerosol cans in place of the CFCs, which can damage the ozone layer very badly. When this reaction occurs in the combustion chamber of a vehicle, 3 moles of gas would be produced from 2 moles, providing an extra boost to the piston, as well as emitting more heat. The increase in heat brings about increased oxygen, which helps in a resourceful combustion of fuel. In turn, the cylinder pressure is also increased which is ably handled by the nitrogen in the gas. And as for the intake temperature, the latent heat of vaporization of the N2O reduces it to a great extent. All these factors when put together, enable a vehicle’s engine to gain more power and provide a boost to its acceleration abilities.
Therefore, N2O is a very resourceful gaseous substance indeed.
Nitrous Oxide (Laughing Gas) Synthesis