210 



INFLUENCE OF ALUMINIUM SALTS ON THE 



Table 2. 



Volume of 



Ammonium 



Sulphate 



used. 



Volume of 



Aluminium 



Chloride 



used. 



Weight of 



Barium 



Sulpliate 



Precipitate. 



Increase in 

 Weight due to 

 the presence of 



Ahiminium. 



CC. 



10.00 



CC. 



grams 

 0.1729 

 0.1738 

 0.5193 

 0.5235 

 0.8650 



1.3838 

 1.3950 

 1.7362 

 1.7501 



grams 



10.00 

 30 00 



25.00 



0.0011 



30.00 

 50 . 00 



25.00 



0.0042 



50.00 

 80.00 



25.00 



0.0064 



80.00 

 100 00 



25.00 

 25.00 



0.0112 



100.00 



0.0139 



From the foregoing results, it is seen tluit the effect of the 

 presence of small quantities of aluniiniuni chloride is to produce 

 a material increase in the weight of the barium sulphate pre- 

 cipitate. With increasing amounts of aluminium chloride and 

 a constant amount of sulphate present, the weight of aluminium 

 taken up by the barium sulphate at first increases and then 

 remains constant, while in the second case, where the amount 

 of sulphate is varied, the degree of contamination of the barium 

 sulphate is proportional to the weight of sulphate used. These 

 results are similar to those obtained by Schneider* for iron. In 

 a solution containing 0.5 gram of ammonium sulphate and 0.025 

 gram of aluminium there would be an error of about 1 per cent, 

 in the estimation of the sulplnir ])resent, as carried out in the 

 ordinary way. 



Although it is well Icnowm that ammonium carbonate cannot 

 be kept in clay or stoneware jars on account of its action upon 

 them, the presence of ammonium carbonate round the gas burner 

 is not sufficient to explain the corrosion of the glass balls in the 



♦Schneider, E. A., Zeit. f. physik. Chcni., 1892, 10, 425 



