Question

Why is Aqua Regia called Royal Water?

Answer 1

As we all know that Aqua regia is known as royal water. Aqua regia is a mixture of concentrated nitric acid and concentrated hydrochloric acid. Usually one part of nitric acid and three parts of the hydrochloric acid by volume. It looks like a yellow- orange colored fuming liquid.

Complete answer:
Aqua regia is a mixture of concentrated nitric acid and hydrochloric acid. The combination of hydrochloric acid and nitric acid are present in a molar ratio of $3:1$ , which means the value could be $65\%$ w/v for hydrochloric acid and $35\%$ w/v for nitric acids. It generally looks like a yellow- orange colored (sometimes red) fuming liquid. It is also called “royal water” or “regal water”. This name was given by Alchemists due to its ability to dissolve gold. The name comes from the Latin “Royal Water” as gold and platinum (royal metals) can be melted.
Agua regia is a nitrohydrochloric acid solution. It is called royal water. This is so because it has the ability to dissolve noble metals like Gold, Platinum. Aqua regia is frequently used to dissolve gold and platinum.
It is also used in analytical procedures for the solution of certain iron ores, nickel-chromium alloys, selenium and some of the less soluble sulfides such as mercury, cobalt and lead etc.

Note:
Aqua regia does not dissolve all the metals. Noble metals like gold and silver can dissolve in it. Aqua regia is extremely corrosive and can cause skin burns. It is used in gold mining processes. It is used to extract organic compounds in trace quantities. It is also used for cleaning glassware.