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.

Why did Max von Laue and James Franck send their Nobel Prize medals to Niels Bohr?

• To have them displayed in a museum

• To protect them from being seized by the Nazis

• To exchange them for other valuables

• To sell them for funding

What characteristic makes a metal 'noble'?

• Its ability to conduct electricity

• Its high melting point

• Its resistance to chemical reactions

• Its magnetic properties

Which of the following metals is considered the least reactive?

• Gold

• Aluminum

• Copper

• Iron

What is Aqua regia composed of?

• One part nitric acid and three parts hydrochloric acid

• Equal parts of sulfuric and acetic acid

• Three parts acetic acid and one part nitric acid

• Two parts hydrochloric acid and one part sulfuric acid

How does Aqua regia dissolve gold?

• By oxidizing it completely

• By forming a stable compound with gold ions

• By melting it at high temperatures

• By evaporating it into gas

What was the state of the gold medals during the war?

• They were melted and recast into bars

• They were hidden in a vault

• They were dissolved in a solution

• They were buried underground

How was the gold eventually recovered after the war?

• By diluting the solution with water

• By heating the solution to evaporate the acids

• By using a chemical to reverse the reaction

• By filtering the solution through a special membrane