230 



ELECTROCHEMISTRY 



It will be observed that as a rule the agreement between the 

 calculated and the observed values of m is excellent and we may 

 therefore conclude that equation (ii) (or (iii)) represents the 

 dependence of conductivity upon dilution, for the salts of the 

 proteins, with very satisfactory fidelity. Recollecting the mode 

 of derivation of equation (ii) this fact might be held to prove that 

 the protein salts, in all of the solutions investigated, dissociate 

 into two ions. This deduction is not altogether a safe one, how- 

 ever. The generalized form of equation (iii) for electrolytes which 

 dissociate into n ions is:* 



m = Ax + Bx n (iv) 



and, provided the departure of equation (iv) from the linear 

 form is small, the factor Bx n may be represented, within the 

 experimental error, by Bx 2 even if n be in reality a higher ex- 

 ponent than 2, while vice versa, Bx 2 may be approximated by 

 Bx n , where n is a higher exponent than 2. For example, in the 

 following table the values of m for calcium caseinate solutions 

 (Cf. Table VI), calculated from formula (iii) and from the formula 



m = A& + iz 3 , (v) 



are compared, f 



TABLE XXIII 



* If the electrolyte dissociates partly into 2, partly into 3, partly into 4, etc., 

 ions the equation becomes: 



m = Ax + Bx* + Cz 3 + Nx n . 



t Sutherland (22) (23), urging the applicability of his theory of ionization 

 to the salts of proteins, has pointed out that the results of Hardy (cited above, 

 Table XIV) obtained with HCl-globulin containing 9.32 X10~ 6 equivalents- of 

 acid per gram of protein may be expressed by the equation: 



- = 0.00026 + 0.009 tr*, 

 M 



in which /t is the molecular conductivity of the salt, calculated in terms of 

 HCl-concentrations, and v is the volume of solution containing one equivalent 

 of Cl. 



