Understand the composition of bleaching powder

Bleaching powder is commonly represented as $CaOCl_2$ but its ionic formulation is better written as $Ca(OCl)Cl$ This shows that it contains:

• one hypochlorite ion, $OCl^-$
• one chloride ion, $Cl^-$

Find oxidation number of Cl in $Cl^-$

In chloride ion, $\text{Oxidation number of Cl} = -1$

Find oxidation number of Cl in $OCl^-$

Let oxidation number of Cl be $x$.

We know:

• oxidation number of O is $-2$
• total charge on $OCl^-$ is $-1$

So, $x + (-2) = -1$ $x = +1$

Conclusion

In bleaching powder, chlorine exists in two different oxidation states:

• $-1$ in $Cl^-$
• $+1$ in $OCl^-$

Therefore, the correct option is: $\boxed{\text{D: } +1 \text{ and } -1}$

Comparison with stored answer

Stored correct answer is D.

My derived answer is also D, so they agree.