acetic and formic acid: general information
formic and acetic acid are the first representatives of unsaturated monocarboxylic acids, so they have similar chemical properties.However, there are a number of differences.
Acetic acid known to man for thousands of years.The word "vinegar" is derived from the Greek "oksos" - so called in ancient Hellas all acids.It is known that if the wine ferment, it becomes acidic.All because of acetic acid, which is formed during the fermentation of wine.Who actually called vinegar 3-15% solution of acetic acid.
Acetic acid is widely used in household cooking and in the food industry.In addition, it is involved in the production of many medicines, in the process of printing books, tissue staining.The chemistry described by acetic acid CH3COOH, and as a food additive code E260 denote it.
Formic acid may be a by-product in some methods the production of acetic acid.Its name it, in fact, obliged to ants in the second half of the XVII century English chemist John Ray got her first time using a secret that ants produce cancer.Now the main field of application of formic acid - Canned food products and animal feed.Chemical formula formic acid - HCOOH, as a food additive code E236 denoted.
How to tell?
Although chemical acetic and formic acid are similar, there are several ways to help distinguish one species from another.The most affordable way - sniff test tubes with chemicals.It is known that acetic acid has a peculiar pungent odor, which is very intense, even in a weak solution.However, when working with concentrated acids should exercise extreme caution, as there is a danger of chemical burns.Therefore sniff test tubes with chemicals may not be safe.
There are other ways to help distinguish the formic acid from the acetic acid.For example - by reaction of the "silver mirror".The fact that the formic acid aldehyde exhibits properties as acetic - no.Therefore, if the tube containing formic acid to add an ammonia solution of silver oxide on the walls of the tubes will be of silver scurf.In the case of acetic acid does not occur.Or you can add the test substance ferric chloride.Formic acid does not change its color, acetic acquire the characteristic red-brown color.
These acids have other distinctive features.Thus, the concentrated acetic acid solidifies into a thick, similar to the ice mass at a temperature of 16 ° C, which is why it is called the wide ice solution.Different and boiling point of these substances are already formic acid boils at 101 ° C, and acetic acid - only at 118 ° C.Furthermore, formic acid, acetic unlike capable of dissolving nylon.Generally, formic acid is 10 times stronger than acetic acid.This should be remembered when working with her concentrate, because even a small amount of it corrodes the skin and can leave severe burns.
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