Aqua regia

Aqua regia is an acid mixture composed of nitric acid and hydrochloric acid. Its common name was given by alchemists because it can dissolve the noble metals gold and platinum.

Properties
Aqua regia is the liquid mixture of nitric acid and hydrochloric acid, the word "Aqua regia" mean royal water or king's water in Latin, the optimal molar ratio for Aqua regia is 1:3. Aqua regia is a fuming liquid with a yellow orange color, it also named because of it can dissolve the noble metal and the platinum. But substances like titanium, niobium, osmium can resist the corrosive properties from aqua regia and not dissolve. Aqua regia has been commonly used to dissolve gold, while nitric acid is a powerful oxidizer it actually dissolve a virtually undetectable amount of gold, forming gold ions Au3+. in addition, gold may be dissolved by the free chlorine present in aqua regia, the appropriate equations are:Au+3NHO3 4HCl=[AuCl]-+3[NO2]+[HO2]+[H3O]+ +2H2O

History
The first aqua regia was mixed by an European alchemist Pseudo-Geber in the early 14th century, He accidentally made the mixture while he tried to made the other substances, the reaction was not reported in modern chemical literature until 1890.,and that all other countries such as Sweden and German had also analyzed aqua regia and gave it new name.

Refining Gold
Because aqua regia is a chemical liquid that can be dissolve many substances,it has been widely use in various way, such as refining gold in a commercial way,list few processes you need: First, before you start refine gold you need breaker coming ware or Pyrex container and hot plate or camping stove,and wooden or plastic spoon for stirring is require. A glass rod can be used. Squeeze bottle, such as a soap bottle,containing distilled water for washing the beaker.Ash-free or coffee filter, and an ash free filter is best, but it costs more and is harder to get one anyway. A plastic funnel or strainer to use with the filter, then in the last one bottle or beaker to filter the liquid into it. And next we are going to consider about is the ingredients that will be use, such like gold or finely powdered ore, a tap water and distill water, un-iodized Salt, Hydrochloric acid, nitric acid, formic acid, sodium sulfite or sodium bisulfite. Then we start refine the gold.

1.place the gold in the beaker that we prepared for, and mix 1:3 ratio for nitric acid and hydrochloric acid in the container.2.move the container on the stove or hot pot until the gold is boil off by the heat.3.make sure all the nitric acid has been boiled off, add a small amount of formic acid. Add hydrochloric acid, if necessary, keep the material covered with liquid. Continue simmering until the nitric acid is gone.5.add a small amount water in it and filter it out from the container

Emergency procedures
Before you testing the Aqua regia you must ready pair goggles, a lab coat, safety gloves and put them on you.While you use the Aqua regia for testing be careful with the accidental exposure may happen.First be aware of having a skin contact with this property,rinse the affected skin immediately with tons of water for about 15 minutes,if necessary please make a safety shower and remove the clothing been contaminated. While you inhaled the Aqua regia move into fresh air immediately,spills should be clean with sodium bicarbonate or the acid neutralizer. About the storage warning is never store Auqa regia with a stoppered bottle, cause it may explode. And when you dispose the Aqua regia pour excess and waste Aqua regia into large amount of ice and fill out a request for pickup of chemical waste,It's a really fatal liquid for human body, so please be really careful when you test it!

Video
A Gold Coin Dissolving in auqa regia XoqU1GfIOkI