Question

What is the oxidation number of gold in the complex $[AuC{l}_4{]}^{1-}$ ?

• A. + 4
• B. + 3
• C. + 2
• D. + 1

Answer 1

Answer: (B)

Let $x$ be the oxidation number of gold $(Au)$ in the complex ${\left[AuC{l}_4\right]}^{-1}$

$\therefore x+4(-1)=-1$

$\Rightarrow x=-1+4$

$\Rightarrow x=+3$

Hence, the oxidation number of gold is +3