10.1021/ie302439u.s001 Hesheng Yu Hesheng Yu Zhongchao Tan Zhongchao Tan Determination of Equilibrium Constants for Reactions between Nitric Oxide and Ammoniacal Cobalt(II) Solutions at Temperatures from 298.15 to 309.15 K and pH Values between 9.06 and 9.37 under Atmospheric Pressure in a Bubble Column American Chemical Society 2013 equilibrium constants 9.37 equations ln KNO 5 pH NH fraction molar basis 9.06 Co ln KNO 6 2 H 2O 298.15 rH kJ 2013-03-13 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Determination_of_Equilibrium_Constants_for_Reactions_between_Nitric_Oxide_and_Ammoniacal_Cobalt_II_Solutions_at_Temperatures_from_298_15_to_309_15_K_and_pH_Values_between_9_06_and_9_37_under_Atmospheric_Pressure_in_a_Bubble_Column/2434819 Experiments were conducted in a bubble column to determine the equilibrium constants of reactions between NO and ammoniacal cobalt­(II) solutions at temperatures between 298.15 and 310.15 K and pH values from 9.06 to 9.37 under atmospheric pressure. The two reactions are 2Co­(NH<sub>3</sub>)<sub>5</sub>(H<sub>2</sub>O)<sup>2+</sup> + 2NO ⇌ (NH<sub>3</sub>)<sub>5</sub>Co­(N<sub>2</sub>O<sub>2</sub>)­Co­(NH<sub>3</sub>)<sub>5</sub><sup>4+</sup> + 2H<sub>2</sub>O and 2Co­(NH<sub>3</sub>)<sub>6</sub><sup>2+</sup> + 2NO ⇌ (NH<sub>3</sub>)<sub>5</sub>Co­(N<sub>2</sub>O<sub>2</sub>)­Co­(NH<sub>3</sub>)<sub>5</sub><sup>4+</sup> + 2NH<sub>3</sub>, respectively. Their equilibrium constants are calculated on the fraction molar basis. All experimental data fit well to the equations ln <i>K</i><sub>NO</sub><sup>5</sup> = 3598.5­(1/<i>T</i>) + 16.759 and ln <i>K</i><sub>NO</sub><sup>6</sup> = 1476.4­(1/<i>T</i>) + 26.597, which give the enthalpy of reactions between NO and penta- and hexaamminecobalt­(II) nitrates: Δ<sub>r</sub><i>H</i><sub>5</sub>° = −29.92kJ·mol<sup>–1</sup> and Δ<sub>r</sub><i>H</i><sub>6</sub>° = −12.27kJ·mol<sup>–1</sup>.