128 § 89. SPECIAL METHODS OF ANALYSIS. 



CHAPTER lY. 



Special Methods of Analysis. 



1. 



COURSE OF QUALITATIVE ANALYSIS. 



89. The following course of analysis is designed as 

 a general guide in qualitative analytical work. Only a 

 single reaction for each substance is mentioned in it, and 

 that is generally the most delicate one ; for fuller de- 

 tails in regard to this particular reaction, and for a few 

 other ones that may in some cases be applied as confirma- 

 tory tests, the student is referred to Chapter III. 



He should, before undertaking to work with the aid of 

 this course, thoroughly familiarize himself, by actual ob- 

 servation, with the behavior of the different acids and 

 bases with reagents, so that he may know what is indi- 

 cated by any particular reaction, the moment he sees it. 



The mode of workiuG^ with the aid of the scheme oriven 

 below is best explained by an example. Suppose we have 

 a solid containing CI, P^O^, SO3, K,Fe, and Mn. Begin- 

 ning with 1 in the left-hand column of figures, in the course 

 for the detection of the acids, the first question is, 

 whether the substance is a soJid or a solution. It being 

 the former, Ave are referred, in the right-hand column of 

 figures to 2 ; going then to 2, in the left-hand column, 

 we find that the solubility of the substance is to bo test- 

 ed ; we apply the solvents in the order there indicated, 

 and find that it is soluble in dilute nitric acid, when wo 

 are referred to G ; going to 6, in the left-hand column, we 

 get no gritty residue on evaporation to dryness, and there- 

 fore no silicic acid is present ; i^assing on to 7, to which 

 we are referred next, we get no such reaction as is de- 



