Microelectrodes C,Au,Pt,Hg each useful in certain solutions/voltage ranges 人 1MH2S04(P) Pt pH 7 buffer(Pt) H1 M NaOH (Pt) 1 M H2SO4 (Hg) H1 M KCI (Hg) Hg H1 M NaOH (Hg) 人 H0.1 M Et NOH (Hg) H 1 M HCIO4 (C) H0.1 M KCI (C) +3+2+10 E(V vs.SCE) Fig 25-4 At-ve limit,oxidation of water 2H20→4H++02(g)+4e At +ve limit,reduction of water 2H20+2e→H2+20H CEM 333 page 12.4 Microelectrodes C, Au, Pt, Hg each useful in certain solutions/voltage ranges Fig 25-4 At -ve limit, oxidation of water 2H2O ® 4H+ + O2 (g) + 4e￾At +ve limit, reduction of water 2H2O + 2e- ® H2 + 2OH￾CEM 333 page 12.4