Reactions with Inorganic Compounds and Ions

The reaction of eh with H2 is very slow ( 105 M-1s-1), due to a positive free energy barrier. Nitrogen has negative electron affinity it is unreactive toward eh. 02 has a high electron affinity, and it reacts with eh with a diffusion-controlled rate (see Table 6.6). The immediate product of the reaction, 02- or its acidic form HOz, reacts further with itself, giving H202and Or 

Both CO and C02 are reduced by eh. The immediate product of the first reaction is CO-, which reacts with water, giving OH and the formyl radical the latter has been identified by pulse radiolysis. The product of carbon dioxide reduction, C02-, is stable in the condensed phase with an absorption at 260 nm. It reacts with various organic radicals in addition reactions, giving carboxylates with rates that are competitive with ion-ion or radical-radical combination rates. 

Oxides of nitrogen are popular electron scavengers. The final product of reaction of eh with N20 is N2 and OH, but the mechanism is not well understood. The rate approaches diffusion control. A possible reactions scheme is 

The gas-phase lifetime of N20- is 10-3 s in alkaline solutions, it is still 10-8 s. Under suitable conditions, N20- may react with solutes, including N20. The hydrated electron reacts very quickly with NO (see Table 6.6). The rate is about three times that of diffusion control, suggesting some faster process such as tunneling. NO has an electron affinity in the gas phase enhanced upon solvation. The free energy change of the reaction NO + eh (NO-)aq is estimated to be --50 Kcal/mole. Both N02- and N03- react with eh at a nearly diffusion-controlled rate. The intermediate product in the first reaction, N02-, generates NO and 

The chemistry of the immediate product N032 in the second reaction is not well understood, but it is presumed that at first N02 is produced, which preferentially hydrates. Thus, the overall reaction is represented by 

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