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?

The man posing as a goldsmith likely used a solution of a strong acid, such as aqua regia, to clean the lady’s gold bangles. Aqua regia is a mixture of concentrated nitric acid (HNO3) and concentrated hydrochloric acid (HCl) in a 1:3 ratio.

1. Aqua Regia Cleaning: When gold is exposed to aqua regia, the strong acids dissolve any impurities, tarnish, or other metals that may have adhered to the surface of the gold, making it appear shiny and new.

2. Dissolution of Impurities: The nitric acid in aqua regia can react with and dissolve impurities or other metals that are present in the gold bangles, leaving behind pure gold.

3. Weight Reduction: The reaction with the strong acids not only removes impurities but also removes a small amount of the gold itself in the form of soluble gold compounds, which are washed away with the solution. This is why the weight of the bangles would have reduced drastically.

The lady observed the bangles sparkling like new because the process effectively removed tarnish and impurities, leaving the pure gold with its characteristic shine. However, the loss of weight is due to the dissolution of some of the gold itself.

It’s important to note that using aqua regia to clean gold should be done with great caution, as it is a highly corrosive and hazardous solution. Only trained professionals should use it, and it’s typically used for refining gold and not for regular cleaning purposes. The man’s actions in this scenario were deceptive and unethical, as he used a dangerous chemical without the lady’s consent.