Question

What is used as a bleaching linen, wood pulp and washed clothes in laundry?
$(A)$ Baking soda
$(B)$ Washing soda
$(C)$ Bleaching powder
$(D)$ Plaster of paris

Answer 1

Hint: The chemical name of bleaching powder is Calcium Hypochlorite. The chemical formula is $CaOC{l_2}$ .It is formed on passing of Chlorine $(C{l_2})$ through Slaked lime or Calcium hydroxide. $(Ca{(OH)_2})$. It is a powder that is pale yellowish and smells strongly like Chlorine.It is soluble in cold water.

Complete answer:
In order to answer the question we need to understand preparation and some properties of Bleaching powder.
The preparation of bleaching powder is as under-
$Ca{(OH)_2} + C{l_2} \to CaOC{l_2} + {H_2}O$
It reacts with dilute acid to produce Chlorine. For example when we react to Bleaching powder with Excess of dilute acid it produces Chlorine gas. It is this Chlorine gas which is responsible for bleaching action.
$CaOC{l_2} + {H_2}S{O_4} \to CaS{O_4} + C{l_2} + {H_2}O$
Now the question is what is the reason for the bleaching action of Chlorine? The reason is that the bleaching process needs moisture and occurs by the oxidation of chlorine.
Chlorine reacts with water and forms hydrochloric acid and hypochlorous acids. This hypochlorous acid is highly unstable and dissociates to form nascent oxygen. This nascent oxygen is a very strong oxidizing agent and its formation is responsible for the bleaching action of chlorine in the presence of moisture.
$\begin{gathered}
  C{l_2} + {H_2}O \to HCl + HClO \\
  HClO \to HCl + \left[ O \right] \\
\end{gathered} $
The nascent oxygen will combine with coloured substances present in the organic matter to oxide them into colourless substances.
Thus due to this chemical change it is used as a bleaching agent in bleaching cotton and linen in textile industries and wood pulp in paper industries. It is also used for bleaching washed clothes in laundry.

All the other given options are not suitable hence Option(C) is correct.

Note:
Apart from this Application bleaching powder is used as a disinfectant and makes water germs free. Also it is used as an oxidant in Industries due to its strong oxidizing nature. It is also used to make wool unshrinkable and for the manufacture of Chloroform $(CHC{l_3})$. Old jewellery or showpieces can be cleaned by bleaching powder.