Question

Chemical formula of Bleaching powder is:
A. $C{a_2}OC{l_2}$
B. $Ca{\left( {OC{l_2}} \right)_2}$
C. $CaOC{l_2}$
D. $CaC{l_2}$

Answer 1

Hint: Try to recall that bleaching powder is prepared by passing chlorine gas through dry slaked lime i.e, calcium hydroxide and the chemical name of bleaching powder is calcium hypochlorite. Now, by using this you can easily find out the correct option for the given question.

Complete step by step solution:
It is known to you that when chlorine gas is passed through dry slaked lime, it forms bleaching powder. The reaction is:
$Ca{\left( {OH} \right)_2} + C{l_2} \to CaOC{l_2} + {H_2}O$
The chemical formula of bleaching powder is $CaOC{l_2}$ and its chemical name is calcium oxychloride or calcium hypochlorite.
It is white powder and has a strong smell of chlorine gas.
It is soluble in water but the solution is not clear due to the presence of impurities in it.
When bleaching powder is treated with dilute hydrochloric acid or dilute sulphuric acid then all the chlorine gas present in bleaching powder is liberated. The reactions are:
$CaOC{l_2} + 2HCl \to C{l_2} + CaS{O_4} + {H_2}O$
$CaOC{l_2} + 2HCl \to C{l_2} + CaC{l_2} + {H_2}O$
Also, it is known that when bleaching powder is exposed to the atmosphere then it reacts with carbon dioxide present in air and produces calcium carbonate and chlorine gas. The reaction is:
$CaOC{l_2} + C{O_2} \to C{l_2} + CaC{O_3}$.
Therefore, from above we can easily say that option C is the correct option to the given question.
Additional information:
Bleaching powder is used for disinfecting drinking water to make water suitable for drinking purposes.
It is also used as an oxidizing agent in many chemical industries.
It is used as a bleaching agent for bleaching wood pulp, cotton and linen in the textile industry.

Note: It should be remembered to you that the bleaching action of bleaching powder is due to the liberation of chlorine gas.
Also, you should know that bleaching powder is also used in the manufacture of chloroform which is used as an anesthetic.