A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

Answer

Gold is one of the least reactive metals, hence it does not react with acids and other substances which can help in cleansing/shining of the gold metal.

• Aqua Regia is a mixture of concentrated HNO3 and concentrated HCl. 
• It is used by jewellers and blacksmiths for dissolution of gold . It is a very corrosive liquid.
• It removes the top corroded layer of gold and returns its shine. 
• When the gold bangles were dipped in it, the upper layer of the gold would’ve dissolved in it, thus resulting in loss of mass of the bangles.