NCERT Question 15 - Chapter 3 Class 10 - Metals and Non-Metals

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.