One day Reeta went to a jeweller's shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?
To polish a gold ornament, it is dipped in a liquid called aqua regia (a mixture of hydrochloricacid and nitric acid in ratio 3:1).
The gold layer starts dissolving when put in aqua regia which causes reduction in the weight of gold amount. The outer layer of gold dissolves and the inner shiny layer appears.