Question

Why do we feel the pungent smell when the pack of bleaching powder is opened?

Answer 1

Hint: The chemical formula of bleaching powder is$CaOC{{l}_{2}}$.$C{{O}_{2}}$ gas is present in the atmosphere which reacts which bleaching powder to produce calcium carbonate and chlorine gas. Chlorine gas has a pungent smell. Bleaching powder is synthesized by the action of chlorine gas ($C{{l}_{2}}$ ) on dry slaked lime ($Ca{{(OH)}_{2}}$)

Complete solution step by step:
Uses of bleaching powder:
- It is used for bleaching dirty clothes in the laundry. It acts as a bleaching agent for cotton and linen in the textile industry.
- It is used as an oxidizer in many industries as it is a strong oxidizing agent.
- It is used as a disinfectant which is used for disinfecting water to make potable water.
Method of preparation of bleaching powder:
Bleaching powder is synthesized by the action of chlorine gas($C{{l}_{2}}$) on dry slaked lime ($Ca{{(OH)}_{2}}$).
$Ca{{(OH)}_{2(s)}}+C{{l}_{2(g)}}\to CaOC{{l}_{2(s)}}+{{H}_{2}}{{O}_{(l)}}$
If bleaching powder is held exposed to air, it reacts with Carbon dioxide gas present in the air to form calcium carbonate and chlorine gas.
$CaOC{{l}_{2}}+C{{O}_{2}}\to CaC{{O}_{3}}+C{{l}_{2}}$
As calcium is required for healthy bones, muscles, nervous system and heart, calcium carbonate is used as a food supplement when the calcium contained in the diet is not adequate.

Chlorine is a gas at room temperature, which has a yellow green colour and an unpleasant pungent smell and because of this chlorine gas we feel a pungent smell when a pack of bleaching powder is opened.

Note: Chlorines is used to clean water and is an integral part of wastewater and industrial waste sanitation cycle. During processing of paper and fabric, chlorine is used as a bleaching agent. Water dissolved chlorine is also used as household bleach. If bleaching powder is held exposed to air, it reacts with Carbon dioxide gas present in the air to form calcium carbonate and chlorine gas.