WATER ANALYSIS 269 



References : 



1. 1501 : 135-139. Drinking Water. 



2. 1503 : 325. Impure Water. 



3. 1702 : 59-61. Impurities in Water. 



4. 1703 : 43-45. Water and its Impurities. 



5. 1710 : 64-78. Tests for the Impurities in Water. 



a. 1706 : 474-475. Simple Tests for Impurities in Water. 



Experiment 88. Water Analysis. 



Apparatus: Ring stand, burner, asbestos mat, evaporating 

 dish, several test tubes. 



Materials: Potassium permanganate solution, 10 per cent, 

 silver nitrate solution, 5 per cent, nitric acid, 1-4, concentrated 

 sulphuric acid, alcoholic solution of castile soap, common salt, 

 distilled water. 



a. Boil to dryness the evaporating dish full of water. The 

 residue is the total solid matter contained in the water. Heat 

 strongly the dried material. If it chars, there is organic 

 matter in the water. Prove it by (6). 



6. Fill one test tube half full of distilled water and another 

 test tube half full of faucet water. To the latter add a bit 

 of paper, and to both a few drops of concentrated sulphuric 

 acid. Now add enough potassium permanganate solution 

 to color each liquid the same tint of light purple. Heat the 

 tube, containing the paper, just to the boiling point, and note 

 the change. Then heat the other tube. Is there any change? 

 To test a sample of water for vegetable material, add a little 

 potassium permanganate and a few drops of concentrated 

 sulphuric acid, and heat to boiling. Bring a sample of water 

 from home, or from some puddle, and test it. 



c. Add a little salt to a test tube half full of water, put in a 

 few drops of nitric acid, and then add a few drops of silver 

 nitrate. The result is silver chloride. Describe it. This 



