ΔH values for the formation of Ni(CN)4(aq)= have been determined calorimetrically at 25° using a simple calorimeter and a thermometric titration procedure at high and low ionic strengths, respectively. Extrapolation of these ΔH values to infinite dilution resulted in a ΔH° value of -42.7 kcal./mole. Combination of ΔH° and ΔF° values gives a ΔS° value of -5.5 e.u. for Ni(CN)4(aq)= formation. A value of +70 e.u. is calculated for the ionic entropy of Ni(CN)4(aq)=. A preliminary investigation of the Zn(CN)4(aq)= system indicated the existence of zinc cyanide complexes other than Zn(CN)4= and allowed calculation of an approximate ΔH° value of -26.5 kcal./mole for the heat of formation of Zn(CN)4(aq)= at 25° and infinite dilution. The heats of neutralization of perchloric and hydrochloric acids with sodium hydroxide have been determined using a non-isothermal, constant-temperature-environment solution calorimeter. The final concentration of the solutions studied varied from 5.0 x 10-3 to 3.5 x 10-2 M. A value of +13.337 ± 0.015 kcal./mole for the heat of ionization of water at infinite dilution was calculated both by extrapolation of the data to infinite dilution and by correction of the data to infinite dilution using the appropriate heat of dilution data. ΔH° and ΔS° values have been determined for the stepwise reaction at 8, 25, and 40° of X- (X = Cl, Br, I) with Hg++ to form HgX2 (aq) and HgX2 (s) (X = I). All data are valid in a solvent 0.10 Fin HClO4 and 0.40F in NaClO4 Relative Hg-X bond strengths in the gaseous pnase and in aqueous solution are discussed. Trends in ΔH° and ΔS° values are discussed in terms of the thermodynamic quantities involved.



College and Department

Chemistry and Biochemistry



Date Submitted


Document Type





Calorimetry, Cyanides, Halides