Royal water or nitro-muriatic acid are other names for aqua regia (the name given to it in 1789 by Antoine Lavoisier).
It’s a 3:1 mixture of hydrochloric acid and nitric acid that’s extremely corrosive.
The acid’s ability to dissolve noble metals like gold, platinum, and palladium is why it’s called royal water.
It does not completely dissolve all noble metals.
Final Answer:
Aqua regia is a mixture of nitric acid and hydrochloric acid in 1:3 ratio.