1. He is one of the first to describe nitric acid, aqua regia, and aqua fortis. c.

2. They examined residues that were left after dissolving crude platinum from the Ural Mountains in aqua regia.

3. It is not attacked by most acids: it is completely insoluble in nitric acid and dissolves slightly in aqua regia.

4. Iridium is the most corrosion-resistant metal known: it is not attacked by almost any acid, aqua regia, molten metals, or silicates at high temperatures.

5. Yet, even refined gold perishes, or dissolves, when exposed to aqua regia (royal water), a mixture of three parts hydrochloric acid and one part nitric acid.

6. Claus showed that ruthenium oxide contained a new metal and obtained 6 grams of ruthenium from the part of crude platinum that is insoluble in aqua regia.

7. (Pharmacology) water: used in compound names of certain liquid substances (as in Aqua regia) or solutions of substances in water (as in Aqua ammoniae), esp in the names of pharmacological solutions