二、Write True (√) or False (×) beside each sentence (20 points

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?