Question

When the three parts of the conc. $HCl$ and one part of conc. $HN{O_3}$is mixed ,a compound $'x'$ is formed. The correct option related to the $'x'$ is:
(A) $'x'$ is known as aqua regia.
(B) $'x'$ is used for dissolving gold.
(C) $'x'$ is used for the decomposition of salts of weak acids.
(D) Both (A) and (B)

Answer 1

Hint- The compound formed by the combination of two strong acids in the concentrated form will make a very strong and exceptional compound. The compound is very energetic, very likely to become hot and also very prone to the explosion. The name of the compound is given by the alchemist due to its dissolving nature of the compound.

Complete step by step solution:
> The two chemicals are hydrochloric acid$(HCl)$ and the nitric acid$\left( {HN{O_3}} \right)$ which are mixed in the molar ratio of $3:1$ ,produce a chemical compound named aqua regia. It is yellow-orange in colour and it also produces fumes. It can dissolve the noble metals like gold and platinum. Due to this dissolving nature of the noble metals it is named as Aqua regia by the alchemists.
> So when we mix three parts of the conc. $HCl$ and one part of conc. $HN{O_3}$, the compound found is known as aqua regia and it can dissolve the gold.
Hence the answer given in the option (A) and option (B) both are correct so the (D) is the correct answer to this given problem.

Note- Solution of this compound named as aqua regia is very corrosive and corrosive material can cause the degradation of the living tissue by the chemicals action. Beside these dangerous qualities of the aqua regia there are many uses of this exceptional compound. It is primarily used to produce chloroauric acid, the electrolyte in the Wohlwill process for refining the highest quality gold. It is also used to clean the glassware of organic compounds and metal particles. Sometimes, it is also known as “royal water” or king’s water.