STANDARDIZING OF TITANOUS SOLUTIONS 367 
TABLE II 
TITRATION OF TITANOUS SULFATE BY ADDITION TO 
PERMANGANATE SOLUTION 
KMn0 4 cc. 
Ti 2 (S0 4 ).3 cc. 
Ti 2 (S0 4 ) 3 0.05 N times 
47.00 
33.35 
1.409 
. 47.08 
33.48 
1.406 
48.91 
34.83 
1.404 
48.86 
34.80 
1.404 
r 
Average 1.4057 
the results in Tables I and II are identical within the limit of ex- 
perimental error. One of us 6 found that permanganate and hy- 
driodic acid could be titrated by running one into the other in- 
terchangeably without apparent difference. 
A new solution of titanous sulfate was made up and standard- 
ized with 0.05 N potassium dichromate solution which was used 
in essentially the same way as the permanganate in the experi- 
ments of Tables I and II. Table III contains the results of its 
titration through the medium of ferric iron. 
TABLE III 
ELECTROMETRIC TITRATION OF TITANOUS SULFATE WITH 
DICHROMATE THROUGH THE MEDIUM OF FERRIC IRON 
K 2 Cr 2 0? cc. 
Ti 2 (S0 4 ) 3 cc. 
Ti 2 (S0 4 )3 0.05 N times 
29.28 
30.40 
0.9631 
29.00 
30.07 
0.9644 
29.80 
30.90 
0.9644 
31.15 
32.30 
0.9644 
Average 0.9641 
The results of the direct titration of titanous salt by adding it 
to dichromate to the end-point are shown in Table IV. 
TABLE IV 
ELECTROMETRIC TITRATION OF TITANOUS SULFATE BY 
ADDING IT TO POTASSIUM DICHROMATE 
K 2 Cr 2 0 7 cc. 
Ti 2 (S0 4 ) 3 cc. 
Ti 2 (S0 4 ) 3 0.05 N times 
25.00 
25.98 
0.9623 
27.83 
28.95 
0.9613 
30.35 
31.51 
0.9632 
30.57 
31.68 
0.9649 
Average 0.96292 
In order to determine the extent to which the standardizations 
with permanganate and dichromate agree and confirm each other, 
6 Hendrixson, Jour. Am. Chem. Soc., 43, 1309 (1921). 
