364 W. E. TOTTINGHAM AND A. J. BECK 



the other hand, ferric chloride was more toxic than manganous 

 chloride and completely antagonized the latter. With regard 

 to the growth of tops the same statements regarding antagonism 

 are true, although manganous chloride was stimulating rather 

 than depressing to this part of the plants. The remarkable 

 stimulating effect of the low plane of ferric chloride suggests 

 that the seed of the variety of wheat here used was notably 

 deficient in reserve iron compounds. 



It appeared probable that the disturbances correlated with 

 the high plane of ferric chloride were due to the acidity known 

 to result from hydrolysis of this salt. On this account a second 

 series of cultures was grown with the addition to the nutrient 

 solutions of sodium bi-carbonate (NaHCOs) to maintain neu- 

 trality.^ 



SERIES 11 



In this series a pure strain of Turkey Red wheat, a winter 

 variety, was grown. Two solutions not employed in Series I 

 were introduced here in duplicate. One of these contained 

 sodium bi-carbonate in the concentration 33^' an amount 

 molecular ly equivalent to the ferric chloride of the low plane 

 of Series I. The other was of the concentration 3^' equivalent 



^ According to the theory of electrolytic dissociation any salt formed by the 

 union of a strong acid with a weak base will react with water and dissociate 

 (hydrolyze) to form free acid. In a similar manner any salt formed from a strong 

 base and a weak acid will yield free alkali. Strong and weak as here used signify 

 the relative extent to which the acid or base is electrolytically dissociated to free 

 ions, the degree of dissociation being proportional to the strength. By this 

 criterion the strength of acids depends upon the concentration of hydrogen ions 

 in its solutions, while the strength of bases depends similarly upon hydroxyl 

 (OH) ions. It is coming to be recognized, however, that both the molecules and 

 the ions may participate in reactions. The following equations illustrate the 

 production of acidity and alkalinity as applied to the present investigation: 



A. FeCU + 3H2O = Fe(0H)3 + 3HC1; HCl = H + CI. 



B. NaHCOs + H2O = NaOH + H2CO3; NaOH = Na + OH. 



Equation A leads to acidity because the electrolytic dissociation of ferric 

 hydroxide (not indicated) is very much less than that of hydrochloric acid. 

 Equation B leads to alkalinity in an analogous manner. Thus the two original 

 salts tend to neutralize each other. 



See: Stieglitz, .Julius, Qualitative Chemical Analysis. 



Part 1 : 178-84, New York, 1912. 



