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The reactions t- [Pt(NH3)2Cl2 ] + OH- ->t- [Pt(NH3)2C1(OH) ] + CIt- [Pt(NH3) 2 Cl(OH)] + OH-- -> t- [Pt(NH3) 2 (OH) 2 ] + Cl in aqueous solutions were studied by measuring the changes in specific conductivity and in ultraviolet absorption which occurred during the course of the reactions. The rates of reaction were determined from a plot of ln L(t) vs time, where L(t) is either (optical density at infinite time)( optical density at time t) for the spectrophotometric determinations or (conductivity at time t) - (conductivity at infinite time) for the conductometric experiments. The conductometric experiments also required correction for hydroxide attack upon the measuring vessel. Both reactions were found to be zero order in hydroxide, to be the only reactions occurring between the platinum complex and the hydroxide for times up to one day, and to involve the formation of an aquo intermediate. The rates for the first hydrolysis were 6. 21 x 10-5 sec -1- at 20 °C, 10. 6 x 10 -5 sec-1 at 25°C, and 29.3 x 10-5 sec-1 at 35°C, with an energy of activation of 18.0 kcal and an entropy of activation of -16 cal/ °K. The rates for the second hydrolysis were 0.17 x 10-5 sec-1 at 25°C and 0. 50 x 10-5 sec-1 at 35°C, with an energy activation of 19.1 kcal and an entropy of activation of -21 cal/ °K.

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