Question

Oxidation number of $Cl$ in $NOCl{O}_4$ is

• A. + 7
• B. - 7
• C. + 5
• D. - 5

Answer 1

Answer: (A)

Calculate oxidation number of $Cl$ in $NOCl{O}_4$ by assuming $Cl{O}_4^{-}$ and $N{O}^{+}$.
Oxidation number of oxygen is $-2$, then oxidation number of chlorine in $Cl{O}_4^{-}$ is
$x+4$(oxidation number of oxygen) $=-1$
$x+4(-2)=-1\Rightarrow x-8=-1$
$\Rightarrow x=-1+8=+7$.