Combination reactions of ions and halogen atoms

It appears that the ion-combination reactions make little or no contribution to the formation of hydrogen100,114. This is reasonable, since clustered H2X+ and X-H-X ions would be expected to reform HX, viz. 

In all three systems the halogen atoms have been assumed to undergo recombination, either in the presence of a third body (s) or on the wall of the reaction cell (t). In HC1 there is also evidence for the reaction 

Two mole per cent sulphur hexafluoride caused only a slight reduction in G(H2). By contrast, in gaseous HC1 2 x 10-2 mole % sufficed to halve the yield of hydrogen from electron reactions. The difference is readily understood since the HC1 concentration in the liquid is such that the reaction 

The effects of chlorine, bromine and ethylene on the hydrogen yields were interpreted in terms of competitions between 

A kinetic analysis of the data gave k22/k22 = 1.7 x 10-3, k22/k14. = 7.9 x 10 4 and k22/kA6 = 7.9 x 10-3. The dependence of G(H2) on the solute concentrations is shown in Fig. 6, where the chlorine and ethylene concentrations have been normalised by multiplying them by the values of k23fkl4t and k46/k1A respectively. These were calculated from the experimental ratios given above. They are summarised in Table 8. 

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