Question

Write the name of the reagent that dissolves Noble metals.

Answer 1

Hint: A reagent is a substance added to a test or system to cause a chemical reaction. Also, the noble metals are metals that resist oxidation and corrosion in moist air. Then strongly oxidizing conditions are required for the dissolution of noble metals. So, we need to find the reagent which is made by strong acids.

Complete answer:
Noble metals are not generally oxidized. To oxidize we need strong oxidation agents. Gold, silver, platinum, mercury, iridium and palladium are such metals which are known as noble metals.
Aqua regia ( $ HN{O_3} + 3HCl $ ) is the mixture of the concentrated nitric acid and hydrochloric acid in a $ 1:3 $ volume ratio. This mixture was also known as “royal water” because of its ability to dissolve gold. It is a red or yellowish liquid. This mixture is one of the strong oxidizing agents and it can be used to oxidize(dissolve) the noble metals.
Palladium, platinum, gold and mercury can be dissolved in aqua regia but iridium and silver cannot dissolve in aqua regia.
Hence, the reagent aqua regia is used to dissolve noble metals.

Note:
Note that the noble metals are not easily attacked by acids and they are the opposite of the base metals. In any chemical reaction, the terms reactant and reagent are frequently used interchangeably.