二、Write True (√) or False () beside each sentence (20 points) 1、Lippmann equation —This is the relationship between the-surface tension, thecharge density, and the-potential applied to the-polarizable interface, for a fixed     。 composition of a solution: q   （）    2、Using the Marcus theory, the charge transfer coefficient-α value can be predicted, and its independence on the potential applied. ( ) 3、 When an electrochemically active compound is present in the solution phase, an anodic current peak at the potential Ep,a is detected with the peak current Ip,a. When the potential is swept back during the reverse scan a further current peak (see Ep,c) may be observed with a cathodic peak current Ip,c. ( ) 4、For electrochemical systems with kinetic constraints in the heterogeneous electron transfer reaction, the following diagnostic criteria can be used in cyclic voltammetry a. the potential separation between the cathodic and anodic peak E p  E p ,c  E p ,a  57 n mV at 25℃ and it increases by increasing the scan rate. ( ) b. the half-wave peak potential (ΔE1/2) does not change by altering the scan rate; ( ) c. the peak currents are proportional to the square root of the scan rate (by redox reactions controlled by diffusion); ( ) 5、 Figure. The effect of the scan rate to the current components of the simulated cyclic ( ) voltammograms of an ErevCirrev reaction。 6、If the chemical step, following the electrochemically reversible electron transfer, is also reversible，then, the diagnostic features of the cyclic voltammograms for such ErevCrev systems are： a. the peak potentials shift for 20/n mV in positive direction per decade increase in the scan rate. ( ) b. the ratio Ip,Red/Ip,Ox (for reduction processes) >1 and it decreases by increasing the scan rate; ( ) c. for slow scan rates, the cyclic voltammograms attain the shape typical for unperturbed simple electron transfer reaction. 7、 ( ) Warburg impedance is a transport-related interfacial impedance element; originated from the diffusion of the electroactive species taking part in the electrode process. ( ) 8、 In electrochemical reactions, the stoichiometric number , is not related to the transfer coefficient of the forward, α, and backward reaction, β. ( ) 9 、If the electrode system consists of a red-ox couple with very large value of i0 so that the current i flowing through the electrochemical cell is always negligible, i.e., i<< i0, the electrode potential will always stay at a value very close to its equilibrium and hardly changes. ( ) 10、 Figure. Effect of the transfer coefficient on the symmetry of the current overpotential curves for O+eR with T=298K and i0=10-6A/cm2。 ( ) 11、 The figure shows that the effect of cation specific adsorption on the electrocapillary curve. a: K+; b: Tl+; c: (C2H7)4N+. The activity of cation follows this order: C2 H 7 4 N   Tl   K  ( ) 12、The exchange current density is a function of the concentration of the oxidized and reduced species, temperature，and the nature of the electrode material. ( ) 13、The electrolyte double layer affects the kinetics of electrode reactions. For charge transfer to occur, electroactive species have to reach at least to the outer Helmholtz plane. Hence, the potential difference available to cause reaction is (ΦM - ΦS) and not (ΦM - ΦOHP)。 ( ) 14、The transient electrode processes and RDE method will eliminate the effect of concentration polarization. ( ) 15、If the rate of conversion of the electroinactive species into the form which can be reduced or oxidized, is slower than the transport by diffusion, a kinetic limiting current result. In such situations the limiting current is controlled by the rate of the chemical reaction, conversion of the electroinactive into the electroactive species. ( ) 16、When overpotential is low, we can measure the polarazation curve in different concentration of component I, namely, the relation between J and Ci were obtainedd when φ is constantly. In the graphic representation of lgJ vs. lg Ci, the slope of the curve will be equal to order of electrochemical reaction. ( ) 三、计算题（10 分） 1、Discuss the mechanism by which the potential of a platinum electrode becomes poised by immersion into a solution of Fe(II) and Fe(III) in 1 M HCl. Approximately how much charge is required to shift the electrode potential by 100 mV? Why does the potential become uncertain at low concentrations of Fe(II) and Fe(III), even if the ratio of their concentrations is held near unity? Does this experimental fact reflect thermodynamic considerations?