Question

Why is aqua regia called royal water?

Answer 1

Aqua Regia:

• Aqua Regia is a combination of three parts concentrated hydrochloric acid $\left(\mathrm{HCl}\right)$ and one part concentrated nitric acid $\left({\mathrm{HNO}}_3\right)$ that is acidic and fuming liquid.
• It is used as a corrosive reagent that is used to clean glassware and it is also used in gold mines.

Royal Water:

• It is also called royal water because it has the ability to dissolve noble metals like Gold, Platinum.
• But it cannot dissolve all metals.

Hence, aqua regia is called royal water.