2. GENERAL METHODS USED
6. OBSERVATION TABLES
Water is the major constituent of all living beings. Water necessary to sustain all types of life. The water used for drinking purpose by human beings should full the following conditions : 1. It should be colourless.
2. It should not possess any smell.
3. It should contain any harmful dissolved salts such as nitrates, mercury salts, lead salts. 4. It should not be contain any living organism such as algae, fungus, bacteria etc. Sterilization of Disinfection of Water
In order to obtain water for drinking purpose, water is first treated with alum whereby clay and other colloidal particles go precipitated the suspended impurities are then removed by filtration and the clear water obtained is subjected to some suitable treatment to destroy harmful germs and bacteria. These bacteria cause many dangerous disease such as cholera, thyroid, dysentery, tuberculosis, diphtheria etc. The process of killing the harmful bacteria by some suitable treatment of water is called STERILIZATION of DISINFECTION OF WATER. The common sterilizer agents are chlorine, ozone, bleaching powder, potassium per magnate chloramines. Sterilization of water through bleaching powder gives chlorine and if it is in excess, it is harmful for health and causes diseases like chlorawis, unconsciousness etc. So here we determine the exact amount of bleaching powder used of required for the sterilization of given samples of water. General Methods of Sterilizing Water
There are many methods of sterilizing water but the best is one which gives sample of water which is totally free from germs. Sometimes potassium per magnate is used to disinfect water but it is not for drinking as it gives red colour and the excess of it is in harmful for health. We use dissolve in water, so it can not be used in large scale. Another method for disinfection is by simply boiling the water for about 15 minutes, but this powder. The chemical action of bleaching powder on germs and bacteria is due to the chlorine which becomes available, when it is added to water. So here in the present context, we shall focus on disinfection of water using bleaching powder. Theory
Objective : Our objective of this project is to determine the amount of bleaching powder required for the sterilization of given samples of water. So certain steps are taken in the context as follows :- 1- A known mass of the given samples of bleaching powder is dissolved in water to prepare a solution of known concentration. This solution contains dissolved chlorine, liberated by the action of bleaching powder with water. CaOCl2 + H2O -------------------> Ca(OH)2 + Cl2
2- The amount of chlorine present in the above solution is determined by treating a known volume of the above solution with excess of 10% potassium iodide solution, when equivalent amount of iodine is liberated. The iodine, thus liberated is then estimated by titrating it against a standard solution of sodium thiosulphate using starch solution as indicator. Cl2 + 2KI --------------------> 2KCl + I2
I2 + 2Na2S2O3 ------------------> Na2S4O6 + 2NaI
3- A known volume of one of the given samples of water is treated with a known volume of bleaching powder solution. The amount of residual chlorines is determined by adding excess potassium iodine solution and then titrating against standard sodium thio-sulphate solution. 4- From the reading in 2 and 3, the amount of chloring and hence bleaching powder required for the disinfection of a given volume of the given sample of water can be calculated. Requirements for the Experimental Determination Requirements are as follows : Apparatus :
2. Titration Flask...