Preparation of plaster of paris, Bleaching powder and bones in kannada for paramedical and dmlt students

Preparation Bleaching Powder:
     

Ca0C12 (calcium oxychloride) is bleaching powder.
  Bleaching powder is produced by the action of chlorine on the dry slaked lime. for a long time.

Ca(OH)2(s) + Cl2(g) — Ca0C12(s) + H20(1)
    
This consists of a vertical cast iron tower fitted with a hopper at the top through which slaked lime is fed and hot air and chlorine enters near the base in opposite direction.

The reaction takes place in the different shelves which contains rotating rakes.

Bleaching powder is collected in the drum kept at the base.

Physical Properties:
1. It is a pale yellow powder.
2.It has strong smell of chlorine.
3.It is soluble in water.
4.It Melting point is 100°C

Chemical Properties:

1. Reaction with dilute hydrochloric acid:- When bleaching powder is reacted with dilute hydrochloric acid then all the chlorine gas present in it is liberated:
   
   CaOCl2+2HCL--->CaCl2+H2O+Cl2
2. Reaction with dilute sulphuric acid:- When bleaching powder is reacted with dilute sulphuric acid then all the chlorine gas present in it is liberated: CaOCl2+H2SO4---->CaSO4+Cl2+H2O

1. Uses of the Bleaching powder :

1) Bleaching powder is also used in the paper industry .

2) Bleaching powder is commonly used for bleaching clothes.

3) Bleaching powder is used to disinfect drinking water.

4) Bleaching powder is used in the manufacture of chloroform (CHCl3), an anaesthetic.

5) Bleaching powder is used as an oxidising agent.

6) Bleaching powder is used to shrink wool.

PLASTER OF PARIS

Preparation of Plaster of Paris

       Plaster of Paris is prepared by heating gypsum (CaSO₄.2H₂O) to a temperature of 373 K in a kiln. Actually the chemical name of gypsum is calcium sulphate dehydrated. 

 when gypsum is heated then it loses one and half molecules of water of crystallization leaving only half molecule of water of crystallization remaining attached with calcium sulphate.

During this process care should be taken not to heat the gypsum above 373K because if gypsum is heated beyond the temperature 373 K then all the water of crystallization is removed from it which results in anhydrous calcium sulphate which is also called as dead burnt plaster.

Uses/Applications:

1. It is used for making toys, cheap ornaments, cosmetics, black-board chalk, decorative materials and casts for statues. 
2. It is used by dentists for making casts of denture.


3. It is used in chemistry laboratories for sealing air-gaps in apparatus where air tight arrangement is required.


4. It is used for making walls of homes smooth before painting them and for making beautiful designs on the ceilings of houses and other buildings.


5. It is also used as a fire proofing materials.

Bone: 

composition and applications:

Made mostly of collagen, bone is living, growing tissue.

Collagen is a protein that provides a soft framework, and calcium phosphate is a mineral that adds strength and hardens the framework. 

This combination of collagen and calcium makes bone strong and flexible enough to withstand stress.

The composition of the mineral component can be approximated as hydroxyapatite (HA), with the chemical formula Ca10(PO4)6(OH)2. However, whereas HA as has a Ca:P ratio of 5:3 (1.67), bone mineral itself has Ca:P ratios ranging from 1.37 - 1.87.