2251
NOTES
systems. I n the Fe2+-Hz02 and Ce4+-Hz02systems, complexes of both HOz. and .OH radicals with Ti4+ ions were observed, as indicated by the two narrow lines in the esr spectra. At a high flow rate of mixing in the Ce4+-Hz02 system, only a narrow singlet spectrum was observed, probably generated by a complex of HOz. radicals with Ti4+ ions. (14) E. Saito and B. H. J. Bielski, J . Amer. Chem. Soc., 83, 4467 (1961). 10 QAUSS
IO OAUSS
Relative Viscosity and Apparent Molal Volume
of Aqueous Sodium Sulfate a t Various Temperatures1
V 10 QAUSS
IO GAUSS
by Frank J. Millero, W. Drost-Hansen, and Lawrence Korson
4
Figure 1. Esr spectra generated in Fe*+-HzO2 and Ce4+-H202 systems in the presence of Ti4+ ions a t 22': (A) Tic14 (23 ml of a 20% solution), FeSO4 (0.01 M), and concentrated HC1 (15 ml) in water (2 1.) mixed with HzOz (15 ml of a 30% solution) and concentrated HC1 (15 ml) in water (2 I , ) ; (B) FeS04 (0.01 M), concentrated HCI (15 ml) in water (2 1.) mixed with HzOa (15 ml of a 30% solution), Tic14 (15 ml of H2Oz oxidized TiCla, 20% solution), and concentrated HC1 (15 ml) in water (2 1.); (C) Ce(SO& (0.001 M ) , Tic14 (20 ml of a 20% solution), and concentrated HzSO4 (15 ml) in water (2 1.) mixed with H202 (23 ml of a 30% solution) and concentrated H2S04 (15 ml) in water (2 1.); (D) Ce(S04)~(0.001 M) and concentrated HzSO4 (15 ml) in water (2 1.) mixed with HZOZ(23 ml of a 30% solution), Tic14 (20 ml of H202 oxidized TiCla, 20% solution), and concentrated H2S04 (15 ml) in water (2 1.). Magnetic field increasing left to right.
Ce4+-H20z systems apparently do not give stable complexes with Fe3+or Cea+ions, respectively. When excess amounts of Fe3+or Ce3+ions were added to the respective systems, no significant effects on the intensity of the esr spectrum resulting from the Ti4+-radical complexes were observed. We have also observed the esr spectrum for the Ce4+-H202 system with a line width of about 24 G, a g value of 2.0165, and a relative signal height of
