Halogens, cyanogen iodide, hypohalous acids and hydrogen fluoride

3 Halogens, cyanogen iodide, hypohalous acids and hydrogen fluoride 

The oxidation of Fe(II) by CI2 is fast ( 2 = 80 + 5 l.mole . sec at 25 X, fi = 3 M) and yields mostly FeCP on the several millisecond time-scale of a stopped-flow apparatus. This does not allow differentiation between one- and two-equivalent mechanisms. The analogous oxidation of hypochlorous acid, ki = 

A conventional study of the ferrous ion-chlorine reaction in a chloride medium indicates the kinetics  

The appearance of FeCl in the Fe (aq) reduction suggests an inner-sphere path. By contrast, the reduction by tris-1 lO-phenanthrolineiron(II) or ferroin is outer-sphere , for ferriin is formed in high yield. The kinetics are simple second-order with (25 °C, n = I M) = 2.2+0.2 (independent of acidity). 

Reduction of bromine by TI(I) is important in the bromide-catalysed isotopic exchange between TI(I) and Tl(III). A potentiometric examination revealed that the reaction was first-order both in T1(I) and in Bt2 with k2 = 7.2 x 10 1. mole . sec (25 °C) and acid-independent. This is in passable agreement with 

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