Question

Chlorine reacts with slaked lime to give _ _ _ _ _ _ _ _ _ powder.

Answer 1

Hint: Slaked lime is \[\text{Ca(OH}{{\text{)}}_{2}}\] and when it is mixed with chlorine, it undergoes a disproportionation reaction with respect to chlorine. Chlorine from 0 oxidation state goes to an oxidation state of +1 in the one of the products and -1 in the other product.

Complete Solution :

On treating slaked lime with chlorine gas, the bleaching agent, calcium hypochlorite is produced industrially. To obtain various compositions each with different concentrations of calcium hypochlorite together with unconverted lime and calcium chloride, the reaction can be conducted in stages.

\[\text{2Ca}{{\left( \text{OH} \right)}_{\text{2}}}\text{+ 2C}{{\text{l}}_{\text{2}}}\to \text{Ca}{{\left( \text{ClO} \right)}_{\text{2}}}\text{+ CaC}{{\text{l}}_{\text{2}}}\text{+ 2}{{\text{H}}_{\text{2}}}\text{O}\]

- Calcium hypochlorite, with formula \[\text{Ca}{{\left( \text{ClO} \right)}_{\text{2}}}\], is an inorganic compound. It is the main active ingredient of commercial products called bleaching powder, also called chlorine powder. Calcium hypochlorite is used for water treatment in swimming pools, drinking water and as a bleaching agent. It is also used in the manufacture of chloroform by haloform reaction. Hence, chlorine reacts with slaked lime to give bleaching powder.

Note: Calcium hypochlorite is a highly basic and is also a strong oxidising agent, used to yield aldehydes or carboxylic acids. For safety, it is stored cold and dry, away from acids, organic materials, and metals.
- In the reaction of chlorine gas with slaked lime, the product with oxidation state of +1 is\[\text{Ca}{{\left( \text{ClO} \right)}_{\text{2}}}\] and that of -1 is \[\text{CaC}{{\text{l}}_{2}}\].