Prof. W. Ostwald's Electrochemical Researches. 117 



equivalent with equivalent. Methylene-disulphonic acid, 

 CH 2 (!S0 2 OH) 2 , is a very strong dibasic acid; solutions of 

 this acid behave similarly to those of nitric acid. 



Methylene-disulphonic Acid, 



CH 2 (S0 2 OH) 2 . 



p- 



v. 



m v 



m 2 . 



on. 



Equiv. 



l 



2 



133-7 



135-1 



134-4 



67-2 



2 



4 



146-0 



146-7 



146-4 



732 



3 



8 



1530 



153-6 



153-3 



76-7 



4 



16 



158-9 



1585 



158-7 



79-4 



5 



32 



163-5 



1640 



163-3 



81-9 



6 



64 



167-7 



167-3 



167-5 



83-8 



7 



128 



171-4 



171-0 



1712 



85-6 



8 



256 



1750 



173-3 



174-2 



87-1 



9 



512 



177-8 



175-9 



1769 



88-5 



10 



1024 



178-8 



177-2 



178 



89 



11 



2048 



179-3 



178-5 



178-9 



89-5 



12 



4096 



179-2 



1772 



178-2 



89-1 



13 



8192 



177-1 



175-7 



176-4 



88-2 



The last column, headed Equiv., shows that the conductivity 

 referred to the equivalent weight (half the molecular weight) 

 of this acid varies in the same way as the conductivity of a 

 strong monobasic acid. The limiting value of the molecular 

 conductivity of dibasic acids, when the second phase of elec- 

 trolysis is traversed, is shown by the numbers in the above 

 table to be twice as large as that for monobasic acids. 



The relations between dilution and conductivity of tribasic 

 and polybasic acids are analogous to those already discussed. 

 Phosphoric acid reacts with two equivalents of alkali to form 

 nearly neutral salts ; the third hydrogen atom is that of a 

 very weak acid. In conformity with these facts, we find the 

 conductivity only slightly increased by great dilution. 





Phosphoric Acid 



,H 3 PO 



4' 





p- 



V. 



on x . 



m 2 . 



on. 



log tan m. 



Diff. 



1 



2 

 3 



4 

 5 



6 

 7 

 8 

 9 



10 

 11 

 12 

 13 



2 



4 



8 



16 



32 



64 



128 



256 



512 



1024 



2048 



4096 



8192 



1421 



16-99 



21-22 



27-05 



34-41 



42-85 



53-1 



61-8 



69-9 



75-4 



79-0 



79-8 



78-9 



14-23 

 17-01 

 21-30 

 27-12 

 34-41 

 43 24 

 53-0 

 '61-8 

 69-6 

 75-4 

 789 

 79-8 

 78-7 



14-22 



1700 



21-26 



27-09 



34-41 



43 05 



531 



61-8 



69-9 



75-4 



790 



79-8 



78-8 



9-4038 

 9-4853 

 9-5900 

 9-7089 

 9-8357 

 9-9704 

 0-1245 

 0-2707 

 0-4366 

 0-5842 



00815 



0-1047 



01189 



0-1268 



0-1347 



0-1541 



0-1462 



01659 | 



01476 



