Question

Why does bleaching powder smell so strongly of chlorine and not dissolve completely in water?

Answer 1

Hint: Try to recall that bleaching powder is prepared by passing chlorine gas through calcium hydroxide solution which is commonly known as slaked lime.

Complete step by step solution:
We already know, the chemical name of bleaching powder is Calcium hypochlorite and the chemical formula of bleaching powder is $Ca\mathop {\left( {OCl} \right)}\nolimits_2$.
It is also known as Chloride of lime.
It is a pale yellowish powder which gives a strong smell of chlorine gas.
Preparation: It is prepared by action of chlorine gas on dry slaked lime.

The reaction is as follows:
$Ca\mathop {\left( {OH} \right)}\nolimits_2 + \mathop {Cl}\nolimits_{2} \xrightarrow{{}} Ca\mathop {\left( {OCl} \right)}\nolimits_2 + \mathop H\nolimits_2 O$.
Also, it has been seen that when bleaching powder reacts with dilute acids, then it produces chlorine gas. The reaction is:
$Ca\mathop {\left( {OCl} \right)}\nolimits_2 + \mathop H\nolimits_2 S\mathop O\nolimits_4 \xrightarrow{{}}CaS\mathop O\nolimits_4 + \mathop {Cl}\nolimits_2 + \mathop H\nolimits_2 O$.
It is also soluble in water but a clear solution is not formed due to the presence of impurities.
It loses chlorine by the action of carbon dioxide. The reaction is:
$Ca\mathop {\left( {OCl} \right)}\nolimits_2 + C\mathop O\nolimits_2 \xrightarrow{{}}CaC\mathop O\nolimits_3 + \mathop {Cl}\nolimits_2$.
So, far we have mentioned all the properties of bleaching powder and also, its preparation.
Now, coming on to the first part of the question, which we have already discussed above, the bleaching powder gives a strong smell of chlorine gas.
We have also discussed above that bleaching powder is completely soluble in water but the solution is not clear due to impurities.

Note: It should be remembered that bleaching water is also used as an oxidizing agent in many chemical industries.
The bleaching action of bleaching powder is due to oxidation and it is permanent.
$Ca\mathop {\left( {OCl} \right)}\nolimits_2 + \mathop H\nolimits_2 O\xrightarrow{{}}Ca\mathop {\left( {OH} \right)}\nolimits_2 + \mathop {Cl}\nolimits_2 \mathop {Cl}\nolimits_2 + \mathop H\nolimits_2 O\xrightarrow{{}}O + HCl$
$COLOR + O\xrightarrow{{}}COLORLESS$
Bleaching powder is also used in the manufacture of chloroform.