چكيده لاتين :
The oxidation of hexacyanoferrate(II) by periodate ion has been studied spectrophotometrically by registering an increase in
absorbance at 420 nm (ƒ max of yellow colored [Fe(CN)6
3-] complex under pseudo first-order conditions by taking excess of [IO4
-]
over [Fe(CN)6
4-]. The reaction conditions were: pH = 9.5 } 0.02, I = 0.1 M (NaCl) and Temp. = 25 } 0.1 oC. The reaction
exhibited first-order dependence on each [IO4
-] and [Fe(CN)6
4-]. The effects of variations of pH, ionic strength and temperature
were also studied. The experimental observations revealed that the periodate ion exists in its protonated forms viz. [H2IO6]3- and
[H3IO6]2- while [Fe(CN)6]4- is present in its deprotonated form throughout the pH region selected for the present study. It has also
been observed that deprotonated form of [Fe(CN)6
4-] and protonated forms of periodate ion are the most reactive species towards
oxidation of [Fe(CN)6
4-]. The repetitive spectral scan is provided as an evidence to prove the conversion of [Fe(CN)6
4-] to
[Fe(CN)6
3-] in the present reaction. The activation parameters have also been computed using the Eyringיs plot and found to be,
ƒ¢H ِ = 51.53 } 0.06 kJ mol-1, ƒ¢S ِ = -97.12 } 1.57 J K-1 mol-1 and provided in support of a most plausible mechanistic scheme for
the reaction under study.
