Kinetics of the reaction of Ni(II) ions with pyridine in water: a polarographic study

The fast ligand-replacement reaction of Ni(II) ion with pyridine in water has been investigated using the reaction-layer treatment of polarographic kinetic currents. Comparison of present results with another polarographic investigation shows discrepancies which are explained. It appears that a surface reaction occurs at the dropping-mercury electrode; by taking this into account we have obtained a rate constant at 25° of 5 × 103 l. mol–1 s–1, and an activation energy of 14 kcal mol–1, in agreement with the values obtained by stopped-flow methods.