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(a) Test for the presence of dissolved lead. 



Into a clean test tube containing some of the sample 

 of water, pour a few drops of hydrochloric acid and a few 

 drops of hydrogen sulphide water and stir the mixture. 



If a slightly brownish color appears, lead is present in the 

 water in sufficient quantity to be harmful. 



() Test for the presence of sewage ; animal impurities. 



Into a clean test tube containing some of the sample of 

 water, pour a few drops of nitric acid and a few drops of 

 silver nitrate, and stir the mixture. If a white precipitate 

 forms, animal impurities are present, and if a strong milk- 

 iness appears, the water is badly contaminated. 



(c) Test for the presence of vegetable impuiities. 



Pour some distilled water into one beaker, and then into 

 another beaker pour an equal quantity of the sample 

 water. To each beaker add a drop of potassium perman- 

 ganate (or sufficient quantity to give the water a faint 

 pinkish tint). Then boil the specimen water for a few 

 minutes, and afterwards allow it to cool. If the color of 

 the cooled tested water is different from the pink tinted 

 distilled water, vegetable impurities are present in the 

 sample water and it is not safe for drinking. 



State your conclusions regarding the quality of your 

 home water supply. 



If possible, secure a sample of spring or pond water 

 from the suburbs and test it in a similar manner. 



The above tests are crude and do not give unfailing 

 proofs of the purity of water. Samples of water might 

 pass these tests and still be unsafe for drinking ; but on 

 the other hand, if samples of water fail to pass these tests, 

 the stream from which they come should not be used as 

 a source of drinking water. 



