Inert gas: Encyclopedia II - Inert gas - Applications

Inert gas - Applications

Because of the non-reactive properties of inert gases they are often useful to prevent undesirable chemical reactions from taking place. For example molecular nitrogen, a molecular inert gas, is often used in food packaging to ensure that food does not spoil in transit since no bacteria or fungi can flourish without the reactive gases oxygen or carbon dioxide, which the molecular nitrogen displaces, since most extant cells on Earth require the reactions which these gases are involved in to function. Most importantly since molecular nitrogen is inert it will not cause any reactions to take place in the food, possibly changing the intrinsic taste or smell, nor will it cause any chemical reactions in the human body. Thus the inert gas is used as a passive preservative, preventing biological decay, while being undetectable to the consumer since taste and olfactory senses require a chemical reaction to take place in order to send a signal to the brain. This is in contrast to active preservatives which react with the biological material of bacteria, fungi, and possibly the food itself changing the food's intrinsic taste or smell, or may even act directly on the consumer's taste and olfactory mechanisms.

In gas metal arc welding inert gases are used to shield the heated metal from the reactive gases in air which can cause undesirable reactions in the metal. Some gases which are not usually considered inert but which behave like inert gases in all the circumstances likely to be encountered in some use can often be used as a substitute for a inert gas. This is useful when an appropriate pseudo-inert gas can be found which is extrememly cheap and easy to come by. For example carbon dioxide is sometimes used in gas metal arc welding because it is not reactive in the circumstances encountered in arc welding even though it is often reactive in other circumstances.

Adapted from the Wikipedia article "Applications", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki