Question

Chemical formula for bleaching powder is:
(A) \[C{a_2}OC{l_2}\]
(B) $Ca{(OC{l_2})_2}$
(C) $CaOC{l_2}$
(D) $CaC{l_2}$

Answer 1

Hint: We know that bleaching powder is solid in nature and comprises Chlorine and slaked lime. It is pale yellow or white colored inorganic powder. It also has a pungent odor in it which is due to the presence of chlorine. Bleaching powder is soluble in water but due to the presence of impurities in it we don’t find a clear solution.

Complete step-by-step answer:The chemical name of bleaching powder is Calcium hypochlorite. So, it is clear that the chemical formula would be $CaOC{l_2}$. Let us see how bleaching powder is prepared:It is prepared by passing chlorine gas over slaked lime
$2Ca{(OH)_2} + 2C{l_2} \to CaC{l_2} + CaOC{l_2} + 2{H_2}O$
Some properties of bleaching powder are: Bleaching powder is basic in nature as when it reacts with hydrochloric acid it releases calcium chloride, chlorine and water so its $pH$ is around $11$.Also, when bleaching powder reacts with carbon dioxide which is present in the atmosphere, it releases chlorine which is why it has a pungent smell like chlorine. The reaction proceeds as:
$2CaOC{l_2} + 2C{O_2} \to 2CaC{O_3} + 2C{l_2} \uparrow + {O_2} \uparrow $
In the presence of insufficient dilute acids, bleaching powder acts as a bleaching agent because nascent oxygen is being released. To understand this let us have a look on the following reaction:
$2CaOC{l_2} + {H_2}S{O_4} \to CaC{l_2} + CaS{O_4} + 2HClO$
This hypochlorous acid formed will further decompose to give hydrochloric acid and nascent oxygen.

Therefore, the correct answer is Option (C).

Note:Bleaching powder is used for bleaching dirty clothes in the laundry as a bleaching agent for cotton and linen in the textile industry. It is also used as a disinfectant which is used for disinfecting water so as to make the water potable. It is used as a strong oxidizing agent and hence is used in many industries.