Question

What is the ratio of $HN{O_3}$ and $HCl$ in aqua regia? What are the applications of aqua regia?

Answer 1

Hint : Aqua regia , the name comes from a Latin phrase which means “king of water”. Aqua regia is a yellow-orange fuming liquid. It was named so because it can dissolve the noble metals gold and platinum, though it does not dissolve all noble metals.

Complete Step By Step Answer:
Aqua regia is a mixture of hydrochloric acid ( $HCl$ ) and nitric acid ( $HN{O_3}$ ) at a ratio of $3:1$ . Generally, concentrated hydrochloric acid is $35\%$ and concentrated nitric acid is $65\%$ .Initially , the solution is colourless, the colour will deepen in order to form an orange red liquid with the smell of chlorine.
It is a reddish-orange or yellowish-orange fuming liquid. Aqua Regia also known as nitro-hydrochloric acid is a highly corrosive mixture of acids. It is a fuming yellow or red solution.
In order to prepare aqua regia, we should pour nitric acid into hydrochloric acid and not hydrochloric acid into nitric acid in order to reduce the risk of splattering hot acid.
Applications of aqua regia are: Aqua regia is primarily used to produce chloroauric acid. Aqua regia is used for dissolving platinum and gold. It is also used as an electrolyte in the Wohlwill process to refine gold of the highest quality.

Note :
Aqua regia solutions are known to be extremely corrosive and may result in explosion or skin burns if not handled with extreme precaution. Aqua regia should be kept only in glass containers because it may melt plastic and corrode metals.