NACE CP2 – EXAM Questions and Answer (with verified
Answers) 2023 (490 Questions)
START OF CHAPTER 1
Corrosion is an electrochemical process involving.
A) flow of protons and electrons
B) flow of neutrons and ions
C) flow of protons and ions
D) flow of electrons and ions
E) flow of resistance and resistivity – correct answer ✅d
Metal loss or corrosion occurs at the
A) cathode
B) anode
C) electronic path
D) metallic path – correct answer ✅b
What are the four parts of the corrosion cell.
A) anode, resistor, electrolyte, metallic path
B) anode, cathode, electron, electronic path
NACE CP2 – EXAM Questions and Answer (with verified
Answers) 2023 (490 Questions)
C) anode, cathode, electrolyte, metallic path – correct answer ✅c
True or False (t or f):
Ions exist only in the electrolyte? – correct answer ✅t
Electrons flow in a corrosion cell by which of the following paths?
A) anode to cathode via electrolyte
B) cathode to anode via electronic path
C) anode to cathode via electronic path – correct answer ✅c
At the cathodic surface in a corrosion cell, the electrons from the _ meet _
ions from the solution.
A) cathode, hydrogen
B) cathode, OHC) anode, hydrogen
D) anode, OH- – correct answer ✅c
NACE CP2 – EXAM Questions and Answer (with verified
Answers) 2023 (490 Questions)
Oxidation of the metal occurs at the _ surfaces and reduction of ions occurs at the ___.
A) anodic, hydrogen, cathodes
B) cathode, OH-, anodic
C) anodic, OH-, cathodes
D) cathode, anodic, electrolyte
E) cathode, hydrogen, electrolyte – correct answer ✅a
True or false
Is oxidation necessarily associated with oxygen? – correct answer ✅f
Current flow in a corrosion cell flows which path:
A) anode to metallic path to cathode
B) anode to electronic path to cathode
C) cathode to metallic to anode
NACE CP2 – EXAM Questions and Answer (with verified
Answers) 2023 (490 Questions)
D) cathode to electrolyte to anode
E) anode to electrolyte to cathode
Voltage is the measure of the electrochemical difference between two electrodes
in an electrolyte – correct answer ✅e
_ is the measure of the electrochemical difference between two electrodes in an electrolyte A) current B) resistance C) error D) ohms E) ohms-cm F) voltage – correct answer ✅f The
represents the reversible work to move a unit charge from the electrode surface
NACE CP2 Study Guide Latest 2023 (Verified answers)
oxidation – correct answer ✅loss of electrons, positive charge atoms
(anode)
reduction – correct answer ✅gain of electrons, negative charged atoms
(cathode)
forms of corrosion – correct answer ✅uniform, crevice, galvanic (dissimilar
metals) if two metals have to be couple then best to couple metals close
together in the galvanic series, pitting, intergranular, selective leaching
(dezincification, graphitization), velocity phenomena, environmental cracking
(corrosion fatigue, hydrogen embrittlement, SCC (Carbonates/bicarbonates)
High PH – correct answer ✅Low hydrogen, alkaline, easy polarization
Low PH – correct answer ✅high hydrogen, acidic, harder to polarize
High oxygen/High Hydrogen concentration – correct answer ✅harder to
polarize, work at the cathode only, called cathodic depolarizers.
NACE CP2 Study Guide Latest 2023 (Verified answers)
factors affecting corrosion – correct answer ✅A. anything that affects
polarization. (temp. etc…)
B. concentration cells (oxygen, temp, etc.) In an oxygen concentration cell,
what is the anode? (i.e. the area with more or less oxygen?) In a metal ion
cell, which area is the anode (i.e. the area with the greater of lower
concentration)?
C. Anaerobic bacteria (MIC) Absence of oxygen, depolarizer
polarization – correct answer ✅a. corrosion current reduces with
polarization
b. polarization increases with CP current applied
c. Occurs at surface of both anode and cathode.
shielding – correct answer ✅a. shorted casings
b. proximity of other structures
c. reinforced concrete
amphoteric materials – correct answer ✅corrode at low and high pH
NACE CP2 Study Guide Latest 2023 (Verified answers)
on potential – correct answer ✅native + polarization + IR drop
polarized potential (off) – correct answer ✅native + polarization
kirchoff’s laws – correct answer ✅a. voltage (series circuits)
b. current (parallel circuits)
faraday’s law – correct answer ✅W=KIT
relates weight loss of metal in a corrosion cell with time and current flow.
rate of corrosion – correct answer ✅directly proportional to current flow
cathodic protection limitations – correct answer ✅-shielding issues
-attenuation
-interference
-excessive current density
-contact with other metals (shorts)
NACE CP2 Study Guide Latest 2023 (Verified answers)
measurement methods – correct answer ✅true voltage reading
voltmeter reading
% error calculations
effect of voltmeter resistance
IR correction methods
test stations – correct answer ✅allow electrical connection to structure for
potential measurements and bonds.
Spans allow current and direction (IR drop).
inistall during construction
pH – correct answer ✅measure of acidity(hydrogen ion concentration)
high pH is alkaline
low pH is acid
pH is a log function therefore each increase in pH is a factor of 10.
RECTIFIER – correct answer ✅- positive to anode
-negative to structure
NACE 2 CBT Study Guide Questions & answers (with
correct answers) 2023
Corrosion is established as a what kind of current? – correct answer ✅Direct
Current
All corrosion of iron at normal ambient conditions is ____
__ – correct answer ✅an electrochemical process.
Define, E=IR – correct answer ✅E is driving voltage, I am current magnitude, R is
circuit resistance.
The less noble part of a corrosion cell – negatively charged – dissolves metallic iron
then converts it to positively charged ions – generates electrons – where oxidation
occurs. – correct answer ✅Anode
The more noble region on the electrode – where electrons are consumed –
positively charged – where reduction occurs – correct answer ✅Cathode.
The difference in potentials between the anode and the cathode create what? –
correct answer ✅Voltage difference, which is the driving force for corrosion.
Allows for electrons generated at the anode to transport to the cathode. – correct
answer ✅Return path (metallic pathway)
NACE 2 CBT Study Guide Questions & answers (with
correct answers) 2023
Conducts ionic current – water-based – contains ions – pathway to transport ions –
carries corrosion current – correct answer ✅Electrolyte.
Negatively charged ions – correct answer ✅Anions
Positively charged ions – correct answer ✅Cations
Four parts to a corrosion cell – correct answer ✅Anode, Cathode, Return Path,
Electrolyte
Oxygen _ the rate of corrosion – correct answer ✅Increases
Corrosion proceeds _ in warmer environments than in cooler ones –
correct answer ✅Faster
Chemical Salts like Sodium Chloride, act as a hygroscopic material (draws moisture
from the air), which _ corrosivity in non-immersed areas. – correct
answer ✅Increases
NACE 2 CBT Study Guide Questions & answers (with
correct answers) 2023
The wetter the environment, the __ corrosion is likely to occur –
correct answer ✅more.
What are the two types of corrosion? – correct answer ✅Localized and General.
Corrosion that occurs in discrete sites on the metal surface – often occurs in areas
difficult to inspect – correct answer ✅Localized.
Corrosion that occurs relatively uniform over the entire surface – correct answer
✅General
What type of corrosion can initiate at an open, freely exposed surface or at
imperfections in the coating? – correct answer ✅Pitting Corrosion.
The type of corrosion that occurs on a metal surface that is shielded from full
exposure to the environment because of the proximity of another material: (ex.
common on support straps, or pipe flanges) – correct answer ✅Crevice Corrosion
The type of corrosion that occurs through the electrochemical action of two
dissimilar metals in contact in the presence of an electrolyte and an electron
conductive path (Return Path): – correct answer ✅Galvanic Corrosion
NACE 2 CBT Study Guide Questions & answers (with
correct answers) 2023
The less effectively the coating insulates the structure, the __ electric
current is required to provide catholic protection. – correct answer ✅more
Two types of Cathodic Protection Systems – correct answer ✅Impressed:
Galvanic.
A device that uses power from electric utility lines to convert the alternating
current to a lower voltage direct current by means of a step-down transformer –
correct answer ✅Rectifier.
What is the minimum requirement for a cathodic protection potential? – correct
answer ✅-0.85V.
What occurs when potential in a cathodic protection system increases (more
negative) – correct answer ✅Hydroxyl formation; Cathodic disbandment Note: if
the potential continues to increase (more negative) disbandment occurs through
the hydrogen process.
Formation of a protective oxide film on the surface reducing its chemical activity
and its ability to corrode – correct answer ✅Passivation.