Question

The IUPAC name of the complex ion formed when gold dissolves in aquaregia is

• A. tetrachloridoaurate $(I)$
• B. dichloridoaurate $(III)$
• C. tetrachloridoaurate $(III)$
• D. tetrachloridoaurate $(II)$

Answer 1

Answer: (C)

tetrachloridoaurate $(III)$

Answer 2

Aqua-regia is a solution containing conc. HCl and conc, $HNO _{3}$ in the ratio $3: 1$. It dissolves noble metals like $Au , Pt$, etc.

$HNO _{3}+3 HCl \longrightarrow 2 H _{2} O +2 Cl + NOCl$
$Au + 3Cl \longrightarrow AuCl3$
$AuCl3 + HCI \longrightarrow \underset{\text{Tetrachloridoaurate (III)}}{4AuCl_4}$