QUESTIONS WITH SOLUTIONS GRADED A+
◉ Polarization _____ the potential difference between the anode and
the cathode and by Ohm's Law, the current ___ and the corrosion rate
____ until an equilibrium is reached
A) lowers, drops, decreases
B) increases, increases, decreases
C) lowers, increases, decreases
D) lowers, drops, decreases. Answer: d
◉ Depolarizers include:
I dissolved oxygen
II microbiological activity
III water flow
A) only I
B) only II
C) I and II
D) I, II , III. Answer: d
,◉ The name for the current that exists during the steady state of
polarization is called the _____ of the system
A) telluric current
B) dynamic current
C) corrosion current
D) mixed potential current
E) closed current. Answer: c
◉ The potential normally measured between the polarized cathode
potential and the polarized anode potential
A) mixed potential
B) corrosion potential
C) corrosion current
D) open circuit potential. Answer: a
◉ _____ are the potentials of the cathode and anode when the
corrosion current is zero
A) mixed potentials
,B) corrosion potentials
C) corrosion current potentials
D) open circuit potentials. Answer: d
◉ ______ is the result of the reaction steps at the structure/electrolyte
interface including the actual transfer of charge
A) activation polarization
B) concentration polarization
C) mixed polarization
D) reactant polarization. Answer: a
◉ In concentrated acids, _______ polarization predominates
A) activation polarization
B) concentration polarization
C) mixed polarization
D) reactant polarization. Answer: a
◉ _______ is the result of reaction steps involving the diffusion of
reactants up to the reaction products away from the reaction surface
, A) activation polarization
B) concentration polarization
C) mixed polarization
D) reactant polarization. Answer: b
◉ Anything that causes a depletion of available reactants or a
buildup of reaction products results in a ____ in the reaction rate and
an
_____ in concentration polarization.
A) decrease, increase
B) increase, decrease. Answer: a
◉ If the slowest step in the overall process involves waiting for
arrival of reactants or the removal of reaction products, the reaction
is under __________ control.
A) activation polarization
B) concentration polarization. Answer: b
◉ If the slowest step in the overall reaction process is is on the metal
surface or in the charge transfer reaction the process is under _____