Question

Does gold dissolve in nitric acid?

Answer 1

Hint: Nitric acid can attack on the gold atoms and can remove gold atoms from the gold piece submerged in it, but those gold atoms get back to the surface of the gold piece. This happens due to equilibrium that is achieved very early.

Complete answer:
The simplest answer to this question would be no, gold does not dissolve in nitric acid. Nitric acid can remove gold atoms from the submerged piece of gold in it, but equilibrium is established quickly and those dissolved gold atoms again get back to the surface of the gold piece.
Even concentrated nitric acid cannot dissolve gold, equilibrium will inevitably establish in it. Nitric acid only turns the gold atoms into gold ions, as gold is still in the form of a single element it will go back to the gold piece.
The chemical formula of nitric acid is \[HN{{O}_{3}}\] and that of gold is \[Au\] .
Although, if the mixture of nitric acid and hydrochloric acid is taken with 1:3 proportion respectively, gold will dissolve in it. This mixture is known as aqua regia. The nitric acid in aqua regia helps gold atoms turn into ions and the hydrochloric acid helps gold ions turn into tetrachloroaurate anion.
After gold turns into ion form, chlorine attacks it to form tetrachloroaurate and as that is a compound of gold, it cannot be separated to simple gold. Thus, gold remains dissolved in the solution. The reaction of it is shown below.
\[Au+HN{{O}_{3}}+4Hcl\overset{{}}{\leftrightarrows}AuC{{l}_{4}}^{-}+NO+{{H}_{3}}{{O}^{+}}+{{H}_{2}}O\]
Nitrogen oxide and water are formed as by-products.

Note:
Although gold and other noble metals can dissolve in aqua regia, they cannot dissolve in either nitric acid or hydrochloric acid separately, however concentrated they are. The functions of both help each other in dissolving the atoms of gold and other noble metals.