Aqua regia facts for kids
Aqua regia is a very powerful acid. Its name means "Royal water" in Latin. It is made by mixing two strong acids: one part concentrated nitric acid and three parts concentrated hydrochloric acid. This special acid got its name from alchemists because it can dissolve "noble metals" like gold and platinum. Most acids cannot do this. However, aqua regia cannot dissolve metals like tantalum or iridium.
Contents
What is Aqua Regia?
Aqua regia is a mix of two strong acids. It is one of the most corrosive mixtures known. This means it can eat away at many materials. It is especially known for dissolving gold and platinum. These metals are usually very hard to dissolve.
How is it Made?
Aqua regia is made by carefully mixing concentrated nitric acid and concentrated hydrochloric acid. It is important to mix them right before use. This is because the mixture starts to break down quickly. It loses its strength if left for too long.
History of Aqua Regia
Aqua regia was first discovered around the year 800 AD. A famous alchemist named Jabir Bin Hayyan found it. He made it by mixing common salt with vitriol (which is sulfuric acid). During the Middle Ages, alchemists used aqua regia. They hoped it would help them find the philosopher's stone. This mythical stone was believed to turn other metals into gold.
A Nobel Prize Story
During World War II, Germany invaded Denmark. A Hungarian chemist named George de Hevesy was working there. He wanted to protect the Nobel Prize medals of two scientists, Max von Laue and James Franck. These medals were made of gold.
To keep them safe from the Nazis, de Hevesy dissolved the gold medals in aqua regia. He put the liquid in a simple jar. He then placed this jar on a shelf in his laboratory. It looked just like hundreds of other jars. The Nazis searched the lab but did not notice the special jar. They thought it contained only common chemicals.
After the war ended, de Hevesy returned to his lab. He found the jar with the dissolved gold. He then used a chemical process to get the gold back out of the solution. He sent the gold to the Royal Swedish Academy of Sciences. The Nobel Foundation then used this gold to make brand new medals for Laue and Franck.
Uses of Aqua Regia
Aqua regia has several important uses today. It is used in different scientific and industrial fields.
- Metal Etching: It helps to create designs on metal surfaces. This is like drawing on metal with acid.
- Scientific Analysis: Scientists use it to study metals. It helps them find out what metals are in a sample.
- Cleaning Lab Equipment: It is very good at cleaning tiny metal particles from lab machines.
- Gold and Platinum Purification: One of its main uses is to extract and purify gold and platinum. This means getting pure gold or platinum from other materials.
Images for kids
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Freshly prepared aqua regia used to remove metal salt deposits.
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Freshly prepared aqua regia is colorless, but it turns orange within seconds. Here, fresh aqua regia has been added to these NMR tubes to remove all traces of organic material.
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Pure gold precipitate produced by the aqua regia chemical refining process.
See also
In Spanish: Agua regia para niños
