Question

With reference to aqua regia, choose the correct option(s)

• A. Aqua regia is prepared by mixing cone. HCI and cone. $HNG_3$ in 3:1 (v/v) ratio
• B. Reaction of gold with aqua regia produces an anion having Au in +3 oxidation state
• C. Reaction of gold with aqua regia produces $NO_2$ in the absence of air
• D. The yellow colour of aqua regia is due to the presence of NOCI and $Cl_2$

Answer 1

Answer: (A), (B), (D)

$\left(1\right) Au + HNO_{3} + 4HCl \rightarrow AuCl_{4}^{\Theta} + H_{3}O^{+} + NO + H_{2}O$
$(2)$ Aqua regia $= 3HCl$(conc.) $+ HNO_3$(conc.)
$(3) AuCl_4^{\Theta}$ is produced
$(4)$ Yellow colour of aqua regia is due to it's decomposition into $NOCl$(orange yellow) and $Cl_2$(greenish yellow).