66o LABORATORY HINTS 



In the emptied flask place 500 c.c. of the water sample. 



Add a pinch of calcined sodium carbonate. 



The ammonium carbonate thus formed yields ammonia readily on 

 boiling. 



Distil and collect the distillate in 50 c.c. Nessler's glasses suc- 

 cessively. 



Add 2 c.c. of Nessler's solution to the first cylinder, stir and let it 

 stand three minutes. 



Match this tint with a standard solution of ammonium chloride 

 (i c.c. = o'ooooi grm. of NHg). 



In a Nessler's glass place 50 c.c. of distilled water. 



Add 2 c.c. of Nessler's solution. 



To this add o'5, or i, or 2 c.c. of the standard ammonium chloride 

 until the tint is the same as the first cylinder distilled. 



If the tint does not match make a fresh standard or have, say, six 

 cylinders containing known and varying amounts for matching. 



Treat the other cylinders the same as thev are distilled over. 



Two or three are usually sufificient and contain all the ammonia. 



Thus the first cylinder recjuires 3*0 c.c. of ammonia chloride solution. 



And the 2nd cylinder requires o"8 ,, ,, ,, 



And the 3rd cylinder requires nil. 



>> 



3-8 c.c. 

 Hence amount of NH3 in 500 c.c. of water is 3'8xo-ooooi. 

 Hence amount of NH3 in 100,000 c.c. of water 



3"8 X O'OOOOI X ico,ooo 



= o'O076 



500 

 = 0*0076 parts per 100,000. 



Save the resulting solution for estimating albuminoid ammonia. 

 Good water does not usually contain more than o'oi parts per 

 100,000. 



(9) To Estimate Albuminoid Ammonia. 



When nitrogenous organic matter is heated with an alkaline 

 solution of KMnO,,, it is oxidized and part of the On present is con- 

 verted into ammonia. 



If the albuminoid ammonia exceeds the saline ammonia it indicates 

 vegetable pollution. 



If the saline ammonia is high and the albuminoid ammonia above 

 0.005 ^vith high figures for saline ammonia it indicates animal pollution. 

 There may be free ammonia in deep well water, the metal of the bore 

 pipes reducing the nitrates. 



Boil in a beaker fifteen minutes 50 c.c. of alkaline permanganate 

 solution with 100 c.c. of water. 



