12 



Mr. W. Sutherland on Ionization in Solutions 



by Walden himself by 10 per cent, on the average, yet the 

 average departure of the individual products X rj in his table 

 from his mean 0'70 is smaller than that in the above table 

 from 0"77. With the data quoted for water bv Walden on 

 pp. 139 and 222 I find that in this solvent N(C 3 H 3 ) 4 I has 

 X =119, */ = 0-00891, so that 100\ ??o = 106, a result which 

 makes water exceptional. The other result which theory 

 requires in the previous table is that K(G/K) shall be con- 

 stant. The range of the departure from constancy in the 

 column K(G/K) is considerable, from 270 to 3150. But 

 G/K is a coefficient, often determined from small changes in 

 X, and liable to large error. The real proof that K(G/K) 

 tends to constancy lies in Walden's discovery discussed above. 

 The mean value of K(G/K) or G obtainable from the table is 

 913. For water G/K is $'$ and K is 81"7, so K(G/K) =718. 

 The striking exceptions to the approximate constancy of 

 A-o^o occur with glycol and water. The exceptional behaviour 

 of water may be connected with the action of ions on its 

 molecules of (H 2 0) 3 and (H 2 0) 3 discussed in "The Molecular 

 Constitution of Aqueous Solutions " (Phil. Mag. [6] xii. 1906, 

 p. 1). The ions in making and unmaking these complex 

 molecules may give the water around them a higher mobility, 

 that is a smaller viscosity, than the average value for water, 

 so the product X tj comes out larger than it ought strictly 

 to do. 



Some data of Carrara's quoted by Walden [Zeitsch. f. pliys. 

 Cliem. xlvi. 1903) for solutions of tri-ethylsulphin iodide 

 S(C 2 H 5 ) 3 I in various solvents show an interesting transition 

 from normal to abnormal solutions. They are given in the 

 following table, the values of X being those estimated by 

 Carrara from his measured values of X. 



Table II. 



Solutions of S(C 2 H 5 ) 3 I at 25°. 



Solvent 



Water 



Acetone 



Methyl alcohol 



Ethyl , 



Allyl 



Propyl ,, 

 Isopropyl „ 

 Isobutyl „ 

 Trimethyl carbinol 

 Isoamyl alcohol .... 



K 



V - 



107-6 



•00891 



167 



•00316 



134 



•0058 



54 



•0108 



32 



•0123 



26 



•020 



22 



•021 



o 



•034 



0-5 



•052 



2 



•037 



100 X 



<>■'/„• 



96 



53 



78 



58 



39 



52 



46 



10 

 2-6 

 7-4 



