Question

What happens when Cl reacts with dry slaked lime?

Answer 1

Hint: It is a pale yellowish powder existing with a strong smell of chlorine. It is soluble in water but due to the presence of impurities, we never observe a clear solution. It is a strong oxidizing agent hence used as an oxidizer in many industries.

Complete step by step solution:
Let us know about bleaching powder!
In the production of bleaching powder, slaked lime is spread on the floors of large rectangular chambers of lead or concrete that is exposed to chlorine gas; or lime is propelled through horizontal tubes that are fed with the gas. Hydrogen peroxide is commonly used to bleach cotton cloth; with sodium chlorite and sodium hypochlorite as alternatives. Its chemical formula is ${ CaOCl }_{ 2 }$ with its chemical name as Calcium hypochlorite. Synthetic fibers are bleached with either oxidizing or reducing agents depending on their chemical composition.

Let us have a look at the preparation of bleaching powder.
Bleaching powder is synthesized by the action of chlorine gas (produced from the chlor-alkali process) on dry slaked lime ${ Ca(OH) }_{ 2 }$

${ Ca(OH) }_{ 2 }+{ Cl }_{ 2 }\longrightarrow { CaOCl }_{ 2 }+{ H }_{ 2 }O$

Uses of Bleaching powder:
It is a strong oxidizing agent hence used as an oxidizer in many industries.
It is used as a disinfecting water to make potable water.

Therefore, Bleaching powder is synthesized by the action of chlorine gas on dry slaked lime.

Note: Bleach is not effective for all pathogens. Contrary to popular belief, bleach does not kill all bacteria. Hard water or extremely soiled surfaces also neutralize the chemical’s disinfecting properties. Surfaces must be cleaned particularly before being treated with bleach.