Question

Select the compound in which chlorine is assigned the oxidation number $+5$.

• A. $HCl{O}_4$
• B. $HCl{O}_2$
• C. $HCl{O}_3$
• D. HCl

Answer 1

Answer: (C)

$HCl{O}_3$

Oxidation state of hydrogen=+1

Oxidation state of oxygen=-2

Let oxidation state of chlorine is x,

In $HCl{O}_4$, $1+x+4(-2)=0,x=+7$

In $HCl{O}_3$ $1+x+3(-2)=0,x=+5$

In $HCl{O}_2$ $1+x+2(-2)=0,x=+3$

In $HCl{}^{}$ $1+x=0,x=-1$

In $HCl{O}_4$, chlorine is assigned the oxidation state of +5.