Question

Two oxidation states for chlorine are found in the compound:

• A. ${CaOCl}_2$
• B. $KCL$
• C. ${KClO}_3$
• D. ${Cl}_2{O}_7$

Answer 1

The correct option is A ${CaOCl}_2$

Solution:- (A) $CaO{Cl}_2$

$CaO{Cl}_2$ consist of hypochlorite $\left({OCl}^{-}\right)$ ion and chloride ion $\left({Cl}^{-}\right)$

The oxidation number of oxygen in hypochlorite ion is -2.

As we know that the sum of the oxidation states of all the atoms in an ion is equal to the charge on the ion.

Let the oxidation number of chlorine in hypochlorite ion be x.

$\therefore$ Oxidation no. of chlorine in ${OCl}^{-}$ ion-

$x+(-2)=-1$

$\Rightarrow x=-1+2=+1$

Therefore, oxidation number of chlorine in ${OCl}^{-}$ is +1.

Oxidation number of chlorine in ${Cl}^{-}$ is -1.

Hence in $CaO{Cl}_2$, the two $Cl$ atoms are in different oxidation states i.e., one as ${Cl}^{–}$ having oxidation number of $-1$ and the other as ${OCl}^{–}$ having oxidation number of $+1$.