Chapter 7 Electrochemistry 87.9 Electrode potential and electromotive forces
Chapter 7 Electrochemistry §7.9 Electrode potential and electromotive forces
Our Goals (1) Calculate unknown potential from given potentials (2)explain the principle for potentiometric analysis ()Construct and apply simple pourbaix diagram
Our Goals (1) Calculate unknown potential from given potentials (2) explain the principle for potentiometric analysis; (3) Construct and apply simple Pourbaix diagram
87.9 Electrode potential and electromotive forces 7.9.3 Relationship between different electrode potentials between different oxidation states Give the relationship between F 2+ Fe Initial state and final state
between different oxidation states Give the relationship between Initial state and final state 7.9.3 Relationship between different electrode potentials §7.9 Electrode potential and electromotive forces
87.9 Electrode potential and electromotive forces 7.9.4 Relationship between different electrode potentials p of relevant electrodes AgCl=Ag cl- rIIna rt k ( Ag(s)AgNO3(c,)llKCI(c2)AgCI(slAg(s) D .IA ne nkp nAcl RT RT 1 e=AgCVAg E Ag /Ag AgCl+ le=Ag+CI- RT n nF RT aAgCI RT 9 AgCl/Ag Exercise: deduce the relationship between Ag(CN)/Ag and Ag/Ag
AgCl = Ag+ + ClAg(s)|AgNO3 (c1 ) ||KCl(c2 ) |AgCl(s)|Ag(s) of relevant electrodes Ag /Ag + AgCl/Ag AgCl/Ag + Ag /Ag E = − sp ln RT E K nF = - Ag(CN) /Ag 2 + Ag /Ag Exercise: deduce the relationship between and 7.9.4 Relationship between different electrode potentials + + + Ag /Ag Ag Ag /Ag Cl Ag /Ag Cl ln ln 1 ln ln sp sp RT RT k a nF nF a RT RT k nF nF a + − − = + = + = + + AgCl + 1e - = Ag + ClAgCl AgCl/Ag AgCl/Ag Ag Cl Cl 1 ln ln RT RT a nF a a nF a − − = + = + §7.9 Electrode potential and electromotive forces
87.9 Electrode potential and electromotive forces 7.9.5 Concentration-dependence of Nernst equation 0=pR7 H, nF for Agt/Ag electrode Pt electrode o RT g/As g nF P(Ag/Ag)depends on [ag], or (Ag/Ag Can we use hydrogen electrode for responds to [Ag]. The relationship between measuring the ph of the solution? P(*/Ag) and [Ag can be used for Give the principle of the measurement. quantitative electroanalysis of Ag
7.9.5 Concentration-dependence of Nernst equation ox red ln RT a nF a = + for Ag+ /Ag electrode + + Ag /Ag Ag /Ag Ag ln RT a nF = + + (Ag+ /Ag) depends on [Ag+ ] , or (Ag+ /Ag) responds to [Ag+ ]. The relationship between (Ag+ /Ag) and [Ag+ ] can be used for quantitative electroanalysis of Ag+ . Can we use hydrogen electrode for measuring the pH of the solution? Give the principle of the measurement. §7.9 Electrode potential and electromotive forces