Photolysis of the Complex Salt Solution

Trisoxalatoferrate(III) solutions, like other analogous complexes of the 3d transition metal series, undergo photoreduction, when irradiated over a range of wavelengths. The system has been studied as a useful actinometer especially when low intensity sources 

Weigh out 0.74 g of your preparation, add 10 cm dilute sulphuric acid and make up to 250 cm with water. Irradiate an aliquot of your solution using a low pressure mercury lamp. Pipette 10 cm of the irradiated solution, add 5.0 cm of the acetate buffer solution used above and 2.0 cm of 0.1% phenanthroline solution, shake well and measure the absorbance at the wavelength of maximum absorption determined in Sec. 13.4.1. Repeat using uranyl oxalate solution described in Sec.2.10.2 but irradiate for a longer period. From O of the latter actinometer, determine d for the trisoxalatoferrate(III) actinometer. 

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