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?

Explanation

Goldsmith dipped the bangles in solution of aqua regia. Aqua regia is a freshly prepared mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3: 1. Aqua regia dissolves considerable amount of gold thus reducing the weight of gold bangles. This fake goldsmith can recover dissolved gold from solution by proper treatment.