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The percentage of the sodium 2.6.8 naphtol disulphonate (G- 
salt) was determined in an analogous way as that of the Scuärrer-salt 
by means of diazotated para-nitraline. The result was 82 °/,. 
For the sodium para phenolsulphonate (technical product) we 
also found 82°/,. The percentage for the dry substance was 87 °/,. 
In reality the percentage of sodium in the dry substance (calculated 
11,7 °/,) was 11,3 "/, (determined with the sulphate-ash method). 
The results with G-salt and sodium para phenolsulphonate in 
alkalie solution are to be found in table VIII. From these investiga- 
tions we see, that 7 milligrammolecules of the technical G-salt 
have bound 6 cm* KOH (0,92 N.) = 5,5 em* N. potassiumhydroxide. 
When we suppose that because of the formula 
SO,Na 
Oa: 
has Noa 
the G-salt behaves like a monobasic acid and at the same time that 
the admixtures, such as the inorganic salts, have no influence 
and that admixtures as other g-naphtolsulphonates have the same 
influence as the G-salt, we should conclude to a percentage of 
> 100 i.e. of nearly 80°/, of constituents that can be bound 
to dyes. 
By titration with diazotated paranitroaniline was found 82 °/,, 
so that in fact it is nearly sure, that in an alkalie solution the 
G-salt behaves like a monobasic acid. 
In an analogous way we may deduce from the observations that 
in alkalie solution the sodium para phenolsulphonate behaves as 
a monobasic acid. 
Delft, Jan. 1920. Laboratory of Chemical Technology Delft. 
len 
Proceedings Royal Acad. Amsterdam. Vol. XXIII. 
