Hiding a Nobel Prize From the Nazis

During WWII, Nobel laureates Max von Laue and James Franck sent their gold medals to Niels Bohr in Denmark to protect them from the Nazis. Chemist George de Hevesy dissolved the medals in Aqua regia to hide them. Aqua regia, a mix of nitric and hydrochloric acids, can dissolve gold by shifting the reaction equilibrium. After the war, the gold was recovered and the medals were remade. This story highlights the chemistry of noble metals and the clever use of reversible reactions.

Explain the concept of equilibrium in chemical reactions as described in the text.

How did the hydrochloric acid contribute to the dissolution of gold in Aqua regia?

What was the outcome of de Hevishi's efforts after the war regarding the gold?