416 ANALYTICAL CHEMISTRY. 



normal, decinormal, etc., solutions deteriorate in time, some very slowly, others 

 rapidly, especially when not properly preserved. To restore the titer of such 

 solutions each time they are to be used involves an unnecessary outlay of time. 

 All that is necessary to know is the exact ratio between the solutions and a normal 

 or decinormal solution, to determine which an accurately standardized solution 

 should be always available. To illustrate, suppose 12.5 c.c. of a hydrochloric 

 acid solution exactly neutralize 10 c.c. of normal potassium hydroxide solution, 

 then 1 c.c. of the hydrochloric acid is equivalent to 0.8 c.c. of normal acid, and 

 the volume of acid used in any titration is readily converted into the equivalent 

 volume of normal acid by multiplying by the factor 0.8. 



Neutralization equivalents. The normal solutions of acid and 

 alkali may be used for the determination of a large number of sub- 

 stances, either directly (as in the case of free acids, caustic and alka- 

 line carbonates and bicarbonates) or indirectly (as in the case of salts 

 of most of the organic acids, with alkalies, which are first converted 

 into carbonates by ignition). 



One c.c. of normal acid is the equivalent of: 



Gramme. 



Ammonia, NH 3 0.01693 



Ammonium carbonate, (NHJ 2 CO 3 0.04770 



Ammonium carbonate (U. S. P.), NH 4 HCO 3 .NH 4 NH 2 CO 2 . . 0.05200 



Lead acetate, crystalHzed Pb(C 2 H 3 O 2 ) 2 .3H 2 6 1 .... 0.18807 



Lead subacetate, Pb 2 O(C 2 H 3 O 2 ) 2 1 0.13593 



Lithium benzoate, LiC 7 H 5 O 2 2 0.12711 



Lithium carbonate, Li 2 CO 3 0.03675 



Lithium citrate, Li 3 C 6 H 5 O 7 2 0.06952 



Lithium salicylate, LiC 7 H 5 O 3 2 0.14299 



Potassium acetate, KC 2 H 3 O 2 2 0.09744 



Potassium bicarbonate, KHCO 3 ....... 0.09941 



Potassium bitartrate, KHC 4 H 4 O 6 * 0.18678 



Potassium carbonate, K 2 CO 3 0.06863 



Potassium citrate, crystallized, K 3 C 6 H 5 O 7 H 2 O 2 . . . .. 0.10736 



Potassium hydroxide, KOH 0.05574 



Potassium permanganate, KMnO 4 3 0.03139 



Potassium sodium tartrate, KNaC 4 H 4 O 6 .4H 2 O 2 . . . ' . 0.14009 



Potassium tartrate, 2K 2 C 4 H 4 O 6 .H 2 O 2 0^11679 



Sodium acetate, NaC 2 H 3 O 2 .3H 2 O 2 0.13510 



Sodium benzoate, NaC 7 H 5 O 2 2 ....... 0.14301 



Sodium bicarbonate, NaHCO 3 0.08343 



Sodium borate, crystallized, Na^CVlOH.O ....'. Q.18966 



Sodium carbonate, monohydrate, Na,CO 3 .H 2 O .... 0.06159 



Sodium carbonate, Na 2 CO 3 0.05265 



Sodium hydroxide, NaOH .... 03976 



Sodium salicylale, Na(C 7 H 5 3 ) 2 ..!!.'.' .' O.'l5889 



One c.c. of normal sodium carbonate, potassium hydroxide, or 

 sodium hydroxide, is the equivalent of: 



i With sulphuric acid and methyl-orange. 2 After ignition. 3 With OX alic acid only. 



