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?
When gold is dipped in aqua regia the outer dull layer dissolves in aqua regia (a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3) and the inner shiny layer appears. Due to this, some gold is lost during the polishing process. This causes a reduction in weight.
[Extra information: Metals: Metals are elements that are malleable, ductile, and can conduct electricity.
Examples: Sodium, Potassium, Copper, Aluminium, Mercury and sodium are metals.
Platinum, gold and silver are used to make jewellery because these are malleable and ductile. These are highly resistant to corrosion.
Sodium, potassium and lithium are very reactive and catch fire when exposed to air. This is due to their low ignition temperature and high reactivity. Sodium is a metal that is so soft that it can be cut with a knife. Silver is the metal that is the best conductor of heat and electricity. ]
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