Question

Select the compound in which chlorine shows oxidation state of $+3$ ?

• A. $ClO _{4}^{-}$
• B. $ClO _{3}^{-}$
• C. $ClO _{2}^{-}$
• D. $ClO ^{-}$

Answer 1

Answer: (C)

Let the oxidation number of $Cl =x$.
(i) $ClO _{4}^{-}: x+(-2 \times 4)=-1$
$x-8=-1, x=+7$
(ii) $ClO _{3}^{-}: x+(-2 \times 3)=-1$
$x-6=-1, x=+5$
(iii) $ClO _{2}^{-}: x+(-2 \times 2)=-1$
$x-4=-1, x=+3 \text {. }$
(iv) $ClO ^{-}: x+(-2)=-1$
$x-2=-1, x=+1$
Thus, $ClO _{2}^{-}$shows oxidation state of $+3$.