tals may be fused for 15 minutes at 220 -250 . 

 C. Approximate Standards: 



Prepare at the beginning of the season about 14 liters of 1.0 N 

 hydrochloric acid by diluting the acid according to the information in 

 the table on the strengths of acids; and of 1.0 N sodium hydroxide by 

 weighing out the proper amount of alkali and making up to volume. 

 Other approximate standards are to be made as required and every effort 

 should be made to issue the proper solution thereby saving the stocks 

 of the specially accurate solutions when these are not required. 



STRENGTH OF STOCK ACIDS AND BASES 



I 



Substance Molecular Molarity Normality Specific Percent Grams/ ml. to make 

 Weight Gravity Liter one 1. of IN 



Acids 



Ammonium 17.03 14.7 14.7 0.90 28(NH3) 252 67 

 Hydroxide 



SOLUBILITY OF COMPOUNDS* 



Solubility is expressed in grams of solute per 100 ml. of solvent at 20 C. 

 KEY: s - soluble sl.s - slightly soluble 



inf - infinitely soluble i - insoluble 



vs - very soluble 

 Substance Formula 



Acid 



Boric H3BO3 



Citric H3CgH50-7«H20 



Oxalic (C00H)2*2H20 



Phosphomolybdic 20Mo03« 2H3P04' 48H2O 



Picric CgH2(OH)2(N02)3 



Tartaric C2H2 (0H)2 (C00H)2 



Trichloracetic CCI3COOH 



Aluminum Chloride AlClo 



•30- 



i 



