Question

Oxidation number of $C{l^ - }$ in $CaOC{l_2}$ (bleaching powder) is:

Answer 1

Hint: At first think about the calculation of the oxidation number of a chemical compound. The oxidation number is also known as the oxidation state and it is defined as the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.

Complete step by step answer:
The chemical formula of bleaching powder is $CaOC{l_2}$ with its chemical name is calcium hypochlorite. The two chlorine atoms are in different oxidation states. The structure of the bleaching order is $Cl - Ca - O - Cl$.
In the structure of bleaching order, one chlorine atom is attached to calcium and the other chlorine atom is attached to an oxygen atom so the two chlorine atoms have different oxidation states.
Coming to the question the oxidation number of chlorine atom attached to calcium atom is $ - 1$and the oxidation number of other chlorine atoms is $ + 1$.
Additional Information:-Bleaching powder is a pale yellowish powder existing with a strong smell of chlorine. It is soluble in water but due to the presence of impurities, we never observe a clear solution. Bleaching powder is synthesized by the action of chlorine gas on dry slaked lime. The reaction is as follows,
$Ca{(OH)_2} + C{l_2} \to CaOC{l_2} + {H_2}O$
It is a strong oxidizing agent, hence used as an oxidizer in many industries. It is used for bleaching dirty clothes in the laundry and it is used as a disinfectant that is used for disinfecting water to make portable water.

Note:
Bleaching powder is basic in character. It gives calcium chloride, chlorine, and water when bleaching powder reacts with hydrochloric acid. It is not highly soluble in hard water and it strongly smells of chlorine.