NACE CP2 ALL COMPREHENSIVE ANSWERS AND
QUESTIONS SURE A+
✔✔the relationship between current and polarization is described by which of the
following?
i. Corrosion cell current decreases with increased polarization.
ii. polarization increases with increased current.
iii. current increases with increased polarization
iv. polarization decreases with increased current - ✔✔i and ii only
✔✔a passivating material will exhibit which of the following properties?
i. does not corrode at all
ii. corrosion increases as current increases initially
iii. corrosion current decreases after a certain point.
iv. corrosion current increases beyond the passive region - ✔✔ii, iii, and iv only
✔✔In a standard emf series of metals, which of the following is represented?
a. the potential of a metal is measured in a saturated solution of copper-sulfate
b. current is measured between the most noble and most active metals.
c. the potential is measured with respect to a standard hydrogen electrode.
d. the total number of electrons is determined. - ✔✔c. the potential is measured with
respect to a standard hydrogen electrode
✔✔if two different metals are connected together in an electrolyte, the metal with the
,a. most negative potential is the cathode
b. most positive potential is the cathode
c. positive potential will corrode
d. highest valence is the anode. - ✔✔b. the most positive potential is the cathode
✔✔in a practical galvanic series of metals, which of the following is represented?
a. the potential between two different metals in the series is measured.
b. the current is measured between two of the metals in the series.
c. the electrolyte contains metal ions of that metal.
d. the potential of metals in a common electrolyte - ✔✔d. the potential of metals in a
common electrolyte
✔✔the nernst equation - ✔✔calculates the potential of a metal in solutions of different
metal ion concentrations
✔✔a corrosion cell can form under which of the following conditions?
a. a difference in temperature where teh higher temperature is the cathode.
b. a difference in oxygen where the highest concentration of oxygen is at the anode.
c. a difference in metals where the anode is at the most noble metal.
d. a difference in salt concentration where the anode is at the highest ion concentration
- ✔✔d. a difference in salt concentration where the anode is at the highest ion
concentration
✔✔when bare metal passes under a paved road surface,
a. an oxygen concentration corrosion cell can develop with the metal under the
pavement being the anode
b. an oxygen concentration cell can develop with the metal outside the pavement being
the anode
c. a temperature corrosion cell can develop with the metal outside the pavement being
the anode.
d. a high salt concentration at the edge of the pavement with the metal under the
pavement being the anode. - ✔✔a. an oxygen concentration corrosion cell can develop
with the metal under the pavement being the anode
, ✔✔an environment where cathodic protection is NOT effective is
a. liquid
b.soil
c.atmospherically exposed surface
d. steel in concrete - ✔✔c. atmospherically exposed surface
✔✔the cathodic protection criteria for steel includes which of the following?
I. a potential of -850 mVCSE or more negative with curent applied after IR drop is
considered
II. a polarized potential of -850mVCSE or more negative
III. polarization of 100 mV or greater
IV. a polarized potential of -790 mv AgAgCl or more negative - ✔✔all of the above
✔✔when cathodic protection is applied to a corroding steel surface, it shifts the
corrosion cell potential -
a. no change in potential
b. cathode more negative
c. cathode more positive
d. anode more positive - ✔✔b. cathode more negative
✔✔cathodic protection polarizes
a. the potential of the structure anode to the structure cathode potential
b. the potential of the structure cathode to the structure anode potential.
c. the potential of the structure cathode to the CP anode potential.
d. the cp anode potential to the structure cathode potential. - ✔✔b. the potential of the
structure cathode to the structure anode potential.
✔✔the current requirement for cathodic protection of a structure will increase with a
a. decrease in pH
b. decrease in temperature
c. decrease in oxygen
d. decrease in velocity - ✔✔a. decrease in pH
QUESTIONS SURE A+
✔✔the relationship between current and polarization is described by which of the
following?
i. Corrosion cell current decreases with increased polarization.
ii. polarization increases with increased current.
iii. current increases with increased polarization
iv. polarization decreases with increased current - ✔✔i and ii only
✔✔a passivating material will exhibit which of the following properties?
i. does not corrode at all
ii. corrosion increases as current increases initially
iii. corrosion current decreases after a certain point.
iv. corrosion current increases beyond the passive region - ✔✔ii, iii, and iv only
✔✔In a standard emf series of metals, which of the following is represented?
a. the potential of a metal is measured in a saturated solution of copper-sulfate
b. current is measured between the most noble and most active metals.
c. the potential is measured with respect to a standard hydrogen electrode.
d. the total number of electrons is determined. - ✔✔c. the potential is measured with
respect to a standard hydrogen electrode
✔✔if two different metals are connected together in an electrolyte, the metal with the
,a. most negative potential is the cathode
b. most positive potential is the cathode
c. positive potential will corrode
d. highest valence is the anode. - ✔✔b. the most positive potential is the cathode
✔✔in a practical galvanic series of metals, which of the following is represented?
a. the potential between two different metals in the series is measured.
b. the current is measured between two of the metals in the series.
c. the electrolyte contains metal ions of that metal.
d. the potential of metals in a common electrolyte - ✔✔d. the potential of metals in a
common electrolyte
✔✔the nernst equation - ✔✔calculates the potential of a metal in solutions of different
metal ion concentrations
✔✔a corrosion cell can form under which of the following conditions?
a. a difference in temperature where teh higher temperature is the cathode.
b. a difference in oxygen where the highest concentration of oxygen is at the anode.
c. a difference in metals where the anode is at the most noble metal.
d. a difference in salt concentration where the anode is at the highest ion concentration
- ✔✔d. a difference in salt concentration where the anode is at the highest ion
concentration
✔✔when bare metal passes under a paved road surface,
a. an oxygen concentration corrosion cell can develop with the metal under the
pavement being the anode
b. an oxygen concentration cell can develop with the metal outside the pavement being
the anode
c. a temperature corrosion cell can develop with the metal outside the pavement being
the anode.
d. a high salt concentration at the edge of the pavement with the metal under the
pavement being the anode. - ✔✔a. an oxygen concentration corrosion cell can develop
with the metal under the pavement being the anode
, ✔✔an environment where cathodic protection is NOT effective is
a. liquid
b.soil
c.atmospherically exposed surface
d. steel in concrete - ✔✔c. atmospherically exposed surface
✔✔the cathodic protection criteria for steel includes which of the following?
I. a potential of -850 mVCSE or more negative with curent applied after IR drop is
considered
II. a polarized potential of -850mVCSE or more negative
III. polarization of 100 mV or greater
IV. a polarized potential of -790 mv AgAgCl or more negative - ✔✔all of the above
✔✔when cathodic protection is applied to a corroding steel surface, it shifts the
corrosion cell potential -
a. no change in potential
b. cathode more negative
c. cathode more positive
d. anode more positive - ✔✔b. cathode more negative
✔✔cathodic protection polarizes
a. the potential of the structure anode to the structure cathode potential
b. the potential of the structure cathode to the structure anode potential.
c. the potential of the structure cathode to the CP anode potential.
d. the cp anode potential to the structure cathode potential. - ✔✔b. the potential of the
structure cathode to the structure anode potential.
✔✔the current requirement for cathodic protection of a structure will increase with a
a. decrease in pH
b. decrease in temperature
c. decrease in oxygen
d. decrease in velocity - ✔✔a. decrease in pH
