Question

When Rita goes to the jeweller to polish her old jewellery the next day she finds the weight of the gold has reduced . How ?

Answer 1

The given sample of gold is dipped in aqua regia or also known as 'royal water' by the jeweler. Aqua regia is a mixture of hydrochloric acid (HCl) and concentrated nitric acid ($HNO_{3}$)

When the given sample is dipped in aqua regia the part of the gold which is not shining and is not bright is removed and in it's place the shinny appearance of gold reapers.

In the way gold is polished and some part of it is removed which results in reduction of it's weight