King water is another name for Aqua regia, a highly corrosive mixture known for its ability to dissolve noble metals.
What is Aqua Regia (King Water)?
According to the reference, Aqua regia is also known as king's water. It is a powerful chemical mixture primarily composed of two strong acids:
- Nitric acid (HNO₃)
- Hydrochloric acid (HCl)
These acids are typically mixed in an optimal molar ratio of 1:3 (nitric acid to hydrochloric acid) to achieve its unique properties. The name "Aqua regia" is Latin for "royal water," reflecting its ability to dissolve the "king of metals," gold.
Why is it Called "King Water"?
The name "king's water" or "royal water" originates from its remarkable capability to dissolve noble metals that are resistant to individual acids. As the reference states, it can dissolve noble metals such as gold, platinum, and palladium. This property was historically significant because gold and platinum were considered "royal" or noble metals due to their resistance to corrosion. Aqua regia was the first known mixture capable of dissolving gold, which is why it earned its regal name.
Key Properties and Uses
The primary distinguishing feature of Aqua regia is its strong oxidizing and complexing abilities, which work in synergy to dissolve noble metals.
- Composition: Nitric acid (HNO₃) and Hydrochloric acid (HCl).
- Optimal Ratio: 1:3 (HNO₃: HCl) molar ratio.
- Key Capability: Dissolves noble metals.
Here's a summary of metals it can dissolve, based on the reference:
- Gold (Au)
- Platinum (Pt)
- Palladium (Pd)
This property makes king water invaluable in various applications, including:
- Refining gold and platinum
- Etching in the production of electronic components
- Chemical analysis
In summary, when someone refers to "king water" or "king's water," they are talking about Aqua regia, a potent acid mixture specifically formulated to dissolve noble metals like gold and platinum.
