No abstract

Measurements of the activity coefficient of NaCl in NaC1-NazS04 electrolytes have been made using the cell Na, HglNaf, C1-, S042-IAgC11Ag, and have been compared with literature values obtained using cation-sensitive glass electrodes. Harned's rule is shown to be obeyed for both components within experimental errors over the ionic strength range from 0 to 6 m.

Potential measurements of the cell TI(1.01 mol in Hg)lTlCl(s)lLi+,Cl-,DMF~Li(1.06 mol % in Hg) have been carried out in an argon atmosphere as a function of time over a range of temperatures from 13.45 to 46.40", and LiCl concentrations from 0.001 to 2.0 m. From these data were calculated standard potentials, free energies,

No abstract

tetrachloride did not remain constant after initial calibration but decreased rapidly toward zero. For example using a 0.1 M sample of DMF in carbon tetrachloride, the AT reading 2 min after the sample drop was placed on the thermistor was 5.20,l min later it was 3.20, and after 15 min AT was 0.03. The rate of AT decrease for DRlA solutions was slightly lower. This behavior would be expected with solutes whose vapor pressures were too high for study by this method and would lead to spuriously high molecular weights.The activity coefficient of NazSOc in aqueous NazS04-h'aC1 electrolytes at 25" and total ionic strength 1.0 has been measured using the cell Pb(Hg)IPbSOl(s)/Na+, S04*-, C1-, HzO/glass electrode where the glass electrode is reversible to Na+. If care is taken to exclude oxygen from the cell during preparation and measurements, reproducibility of the order of &0.05 mV is obtained. Harned's rule was found to be obeyed within experimental error for Na2S04 (component 2) in these mixtures, and the coefficient aZl at I = 1 was calculated by a least-squares method to be -0.035 i 0.005. This agrees with the value of azl calculated from published osmotic coefficients and activity coefficients of NaCl (component 1) in the corresponding mixtures.