PH effects in the γ-radiolysis of aqueous solutions

Abstract

From the effects of nitrous oxide on the radiation chemistry of aqueous solutions containing either (i) acrylamide, or (ii) potassium ferrocyanide and ferricyanide, the following conclusions are drawn. (1) G H 2 and G H 2 O 2 diminish only slightly as pH is increased from pH 0 to 13.5. (2) At 4.5 ⩽ pH ⩽ 12, G e- = 2.8 and G HO = 2.3, but as the pH is increased to 13.5 both these quantities increase by about 1 unit, an effect which is attributed to the reaction of OH - with either radical pairs (H + OH) or excited water molecules H 2 O*, i.e. (H + OH) or H 2 O* + OH - → e aq . + OH. (3) Solutes are divisible into three categories according as they (a) react with e aq . only, or (b) quench H 2 O*, or provide an alternative route for H + OH recombination, or (c) react with e aq and H atoms to give distinguishable stable products. (4) k ( e - aq . +ferricyanide)/ k (e aq ._ + N 2 O) = 0.60 + 0.15 at [i = 0.013 but increases with u in a way which indicates that e aq . has unit negative charge and survives long enough for the establishment of its ionic atmosphere. (5) k (e aq . +H + aq. )/ k (e aq ._ + N 2 O) = 0.65 + 0.35, +acrylamide)/ k (e aq . + N 2 O) = 1.2 + 0.2 and k (H + ferrieyanide)/ k (H + N 2 O) = 625+100. The passage of a fast charged particle through aqueous systems causes ionizati