Question

Which of the following metal (is/are) soluble in aqua regia?
A.Pt
B.Au
C.Hg
D.All of these

Answer 1

Hint: Reactivity is basically the ability of an element to form bonds with other chemical species. Bonds are formed when there is either sharing of the electrons (covalent bonds) or transfer of electrons (ionic bonds).

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Certain elements like gold and platinum are placed very low in the reactivity series of elements. These metals that show very little to no reactivity are known as noble metals. Most of the common reagents like air water show no corrosive effects on metals like gold and platinum. Along with the common reagents, even some really powerful or strong acids are not able to even react with these metals, let alone dissolve them.
In the case of a metal like gold, the valence 6s subshell has only 1 electron, but it is very tightly bound to the nucleus. Hence its reactivity is not as expected from an atom with a single electron in the valence shell.
Even though almost no compound is able to dissolve gold or platinum, there is a compound named aqua regia that can dissolve gold and platinum. Aqua regia is formed when we mix 3 parts of hydrochloric acid with one part of nitric acid. Since this compound can dissolve gold and platinum it has the potential of dissolving literally any other metal.

Hence, Option D is the correct option

Note: Aqua regia is widely used today in the industries that involve working with metals like gold and Platinum. Since this compound is extremely corrosive, it must be handled with utmost care and all safety rules must be followed.