Dissociation Constant and Degree of Dissociation for

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4425

ADDITIONS A N D CORRECTIONS

1964, Volume 68 Kinko Shinzawa and Ilkuzo Tanaka : The Photochemical Isomerization of a,N-Diphe nylnitrone. Page 1205. I n line 10 of the Abstract, 0.28 should read 0.56, and 0.18 should read 0.36. Pages 1210 and 1211. I n Figures 5 and 8 the values of the vertical axes should be doubled.-KrNxo KOYANO. M. M. Breuer: The Binding of Phenols by Hair. 11. Volume Changes Accompanying the Dilution of Aqueous SOlutions of Phenols. Page 2078. The sentence commencing on line 35 of the first column should read: The respective heats and entropies of association calculated from the values of Kl and Kz and the heats of dilution (Figure 6) in an analogous way as described before are +650 cal./mole, f1600 cal./mole, - 1.60 e.u./mob, and $2.23 e.u./mole.-M. M. BREWER.

Y. Marcus and M. Givon: Anion Exchange of Metal Complexes. XIV. The Effect of Acidity on the Sorption of Lanthanides from Lith’,um Nitrate Solutions. Page 2233. The view that dimerization of nitric acid has been found in a solution of a trialkylamine in toluene has been erroneously attributed to Hogfeldt and Fredlund (ref. 19), being based on a pre-publication copy of their paper [Acttc Chem. Xcand., 18, 543 (l964)], kindly supplied by Dr. Hogfeldt. Their paper only supports the formation of the dimeric complex (R3N HN0&. The formation of the species RaNH+. (Nos“Os)has, however, recently been proposed by Tuck and coworkers [J. Bullock, s. Choi, D. Goodrick, D. Tuck, and E. Woodhouse, J . Phys. Chem., 68, 2687 (1964)l to explain their data on similar systems. The conclusions of the present paper are not based on species which may be present in amine systemfi, however.-Y. MARCUS. Harold W. Kohn : Oxidation of Hydrocarbons Adsorbed on Oxide Catalysts Induced by Cobalt-60 pRays. Page 3134. The sentence beginning on the third line below eq. 4 should read: If 3 is zero order or fast., .(instead of slow). -HAROLDW. KOHN.

Heats of Formation of Anhydrous Europium(I1) Chloride and of the Aqueous Europium(I1) Ion. Page 991. I n the Abstract, the value of the heat of formation of EuClz(s) is reported incorrectly as -195.8 kcal./mole; it should be the same as that found in the text on p. 995, viz., - 192.8 kcal./mole.-C. T. STUBBLEFIELD. Richard P. Wendt : The Estimation of Diffusion Coefficients for Ternary Systems of Strong and Weak Electrolytes. Page 1229. Line 18, column 1, should read: Bz4,and Cz6, respectively. Valences of the ions. . , . Page 1233. I n eq. 59, the last term in the bracket should read YiEVhG Yl&

+

YZGCZ

RICHARD P. WENDT

D. W. Placzek, D. F. Ring, and B. S. Rabinovitch: Deuterium Isotope Effects on Rates of Methylene Radical Insertion into C-H Bonds. Page 1783. In column 2, lines 13-16, a kinetic equation of Majer, Capey, and Robb [J. R. Majer, W. D. Capey, and J. C. Robb, Nature, 203, 294 (1964)l was termed inexact and a “more exact” formulation was cited (D. W. Placzek, Ph.D. Thesis, University of Washington, 1965). We thank Professor Robb for calling our attention to an arithmetic error in our derivation, correction of which renders it into his form which is exact. No results, computations, or conclusions are affected.-B. S. RABINOVITCH.

M. L. Hyder : The Radiolysis of Aqueous Nitrate Solutions. Page 1858. A systematic error has been found in the calibration techniques used in this work which decreases all G values reported in the article. Correct G values may be obtained by multiplying the published values by 0.83. As a result, the measured value of G,,,- is decreased to 3.2 and the derived value of G - E ~ Obecomes 3.9, These values are close t o those reported by others who have studied alkaline solutions, including, in particular, Cheek and Linnenbom [C. H. Cheek and V. J. Linnenbom, J . Phys. Chem., 67,1856 (1963)l. The qualitative conclusions discussed in this article are not affected by t,his correction.-M. L. HYDER.

1965, Volume 69 David L. Lydy, V. Alan Mode, and Jack G. Kay : Dissociation Constant and Degree of Dissociation for Tetraethylammonium Chloride in Ethylene Dichloride a t 0, - 15, and - 30’. Page 88. I n Table 11, Professor C. W. Davies has brought to our attention that the calculated minima in the degree of dissociation curves are much dependent upon the particular activity coefficient equation used. The relationship log f* = -A z / Z gives the best agreement between calculated and observed values for the dissociation minima. The third column of Table 11, calculated on the basis of this limiting Debye-Huckel equation, should be corrected to read 1.92, 2.21, and 2.43 for t!he temperatures 0, -15, and -30”, respectively. The factor 5.3 is ehinated.-JAcK G. KAY. C. T. Stubblefield, J. L. Rutledge, and R. Phillips:

The

Douglas C . Poland and Harold A. Scheraga: Hydrophobic Bonding and Micelle Stability. Page 2442. We erroneously stated that “there is a glaring discrepancy between theory and experiment when the dependence of AN (for formation of the micelles) on chain length is considered.” Actually, the experimental AH becomes more negative as chain length increases. This is exactly what the theory predicts [(a) G. Nemethy and H. A. Scheraga, J . Chem. Phys., 36, 3401 (1962), Figure 7 . Figure 7 applies t o the solution process; in applying it to the reverse process, the sign of AH must be changed. (b) G. Nemethy and H. A. Scheraga, J . Phys. Chem., 66, 1773 (1962), eq. 21 and the discussion following Table XI.] for straight-chain hydrocarbons; in the branched side chains of amino acids, the enthalpy of formation of a hydrophobic bond does become more positive as one goes from alaninealanine to valine-valine to isoleucine-isoleucine (either in pair-

Volume 60, Number 18 December 1966