NACE CP2 Exam | Cathodic Protection Technician Level 2 | Questions with Cor
OBJECTIVE ASSESSMENT - EXAM
NACE CP2 Exam
Cathodic Protection Technician Level 2
A+ Verified Edition: 2026/2027 Passing Score: 70% Marks: 100 Total
COVER PAGE - 1
,SECTIONS COVERED
Section 1: Corrosion Theory and Electrochemistry (Questions 1-20)
Section 2: Electrical Fundamentals and CP Systems (Questions 21-40)
Section 3: Field Testing and Measurements (Questions 41-60)
Section 4: Stray Current, Interference, and Troubleshooting (Questions 61-80)
Section 5: Safety, Codes, and System Maintenance (Questions 81-100)
EXAM INSTRUCTIONS
This examination assesses intermediate-level knowledge of corrosion theory, cathodic protection concepts,
and advanced field measurement techniques. Read each question carefully and select the best answer.
Subject: NACE CP2 Exam | Cathodic Protection Technician Level 2 | Questions with Correct Verified Solutions | 100% Pass G
Difficulty: Professional certification requiring technical knowledge and field application
Question Type: Multiple choice, 4 options (A-D)
Marks: 1 mark per question, 100 marks total
Passing Score: 70%
Bloom's Taxonomy: Application/Analysis
, Section 1: Corrosion Theory and Electrochemistry
Question 1
A buried carbon steel pipeline in a coastal marsh shows pitting corrosion concentrated at the six o'clock
position. The soil pH is 7.2 and dissolved oxygen levels are lowest at the pipe bottom. Which
electrochemical mechanism best explains this localized attack?
A. Differential aeration cell formation due to oxygen concentration gradients
B. Galvanic coupling with copper grounding rods nearby
C. Microbiologically influenced corrosion from sulfate-reducing bacteria
D. Stray current discharge from an adjacent impressed current system
Correct Answer: C
Rationale: Sulfate-reducing bacteria thrive in oxygen-depleted, moist environments and produce hydrogen sulfide, causing
localized pitting at the pipe bottom. While differential aeration (A) causes corrosion, it typically attacks the oxygen-starved area
differently, and the scenario specifically describes conditions ideal for MIC.
Question 2
During a pipeline inspection, a technician measures a structure-to-electrolyte potential of -0.420 V CSE on
bare steel in aerated soil. When the cathodic protection system is energized, the potential shifts to -0.920
V CSE. Which polarization component contributes most significantly to this 500 mV shift?
A. Concentration polarization from hydroxide ion accumulation
B. Activation polarization at the cathodic surface
C. Ohmic drop through the soil electrolyte path
D. Resistance polarization from surface film formation
Correct Answer: B
Rationale: Activation polarization dominates at the cathode during cathodic protection because the hydrogen evolution
reaction requires an overpotential to drive the reaction. Concentration polarization (A) becomes significant only at high current
densities or in stagnant conditions, which are not described here.
Question 3
A zinc anode coupled to steel in seawater produces a measured current of 2.3 A. Over six months, the
current decays to 1.1 A while the steel potential remains protective. Which factor is the primary cause of
this current reduction?
A. Increased calcareous deposit formation on the steel cathode
B. Passivation of the zinc anode surface
C. Increased seawater temperature raising conductivity
D. Cathodic disbondment of the pipeline coating
Correct Answer: A
Rationale: Calcareous deposits (calcium and magnesium compounds) form on the cathodically protected steel surface,
increasing polarization resistance and reducing current demand. This is a normal and expected phenomenon in seawater CP
systems. Zinc anodes do not passivate (B) in seawater.
, Question 4
In a laboratory corrosion cell, a steel specimen shows a corrosion rate of 0.85 mm/year when the pH is
6.0. When the pH is raised to 9.5 with the same dissolved oxygen content, the corrosion rate drops to 0.12
mm/year. Which electrochemical principle explains this behavior?
A. Formation of a passive oxide film at higher pH
B. Decreased cathodic reaction kinetics in alkaline conditions
C. Reduced ionic conductivity of the electrolyte
D. Increased hydrogen evolution suppressing oxygen reduction
Correct Answer: A
Rationale: Steel forms a protective passive oxide film (magnetite) in alkaline environments, dramatically reducing corrosion
rates. While cathodic kinetics do change with pH, the primary mechanism for this magnitude of reduction is passivation.
Hydrogen evolution (D) is not significant in this pH range with oxygen present.
Question 5
A copper pipe connected to a galvanized steel water heater shows severe corrosion at the steel
connection after two years of service. The water conductivity is 450 µS/cm and temperature is 55°C.
Which factor most accelerates this galvanic corrosion?
A. The large cathode-to-anode area ratio favoring steel dissolution
B. The low conductivity water preventing current flow
C. The elevated temperature increasing exchange current density
D. The formation of a zinc hydroxide passive layer on the galvanized coating
Correct Answer: A
Rationale: Galvanic corrosion severity is directly proportional to the cathode-to-anode area ratio. Copper (noble cathode)
connected to zinc-coated steel (active anode) with a large copper surface area drives high current density at the steel
interface. Temperature (C) accelerates kinetics but area ratio is the dominant factor.
Question 6
A pipeline operator observes that corrosion rates increase significantly during summer months when soil
moisture content rises from 12% to 28%. The soil resistivity drops from 8,000 Ω·cm to 2,500 Ω·cm during
this period. Which relationship best describes this behavior?
A. Corrosion rate is inversely proportional to soil resistivity
B. Corrosion rate increases linearly with moisture content above 15%
C. Corrosion rate is independent of resistivity below 10,000 Ω·cm
D. Corrosion rate decreases as electrolyte conductivity improves
Correct Answer: A
Rationale: Lower soil resistivity indicates higher electrolyte conductivity, which facilitates ionic current flow between anodic and
cathodic sites, accelerating corrosion. The inverse relationship between corrosion rate and soil resistivity is well-established in
corrosion science.
OBJECTIVE ASSESSMENT - EXAM
NACE CP2 Exam
Cathodic Protection Technician Level 2
A+ Verified Edition: 2026/2027 Passing Score: 70% Marks: 100 Total
COVER PAGE - 1
,SECTIONS COVERED
Section 1: Corrosion Theory and Electrochemistry (Questions 1-20)
Section 2: Electrical Fundamentals and CP Systems (Questions 21-40)
Section 3: Field Testing and Measurements (Questions 41-60)
Section 4: Stray Current, Interference, and Troubleshooting (Questions 61-80)
Section 5: Safety, Codes, and System Maintenance (Questions 81-100)
EXAM INSTRUCTIONS
This examination assesses intermediate-level knowledge of corrosion theory, cathodic protection concepts,
and advanced field measurement techniques. Read each question carefully and select the best answer.
Subject: NACE CP2 Exam | Cathodic Protection Technician Level 2 | Questions with Correct Verified Solutions | 100% Pass G
Difficulty: Professional certification requiring technical knowledge and field application
Question Type: Multiple choice, 4 options (A-D)
Marks: 1 mark per question, 100 marks total
Passing Score: 70%
Bloom's Taxonomy: Application/Analysis
, Section 1: Corrosion Theory and Electrochemistry
Question 1
A buried carbon steel pipeline in a coastal marsh shows pitting corrosion concentrated at the six o'clock
position. The soil pH is 7.2 and dissolved oxygen levels are lowest at the pipe bottom. Which
electrochemical mechanism best explains this localized attack?
A. Differential aeration cell formation due to oxygen concentration gradients
B. Galvanic coupling with copper grounding rods nearby
C. Microbiologically influenced corrosion from sulfate-reducing bacteria
D. Stray current discharge from an adjacent impressed current system
Correct Answer: C
Rationale: Sulfate-reducing bacteria thrive in oxygen-depleted, moist environments and produce hydrogen sulfide, causing
localized pitting at the pipe bottom. While differential aeration (A) causes corrosion, it typically attacks the oxygen-starved area
differently, and the scenario specifically describes conditions ideal for MIC.
Question 2
During a pipeline inspection, a technician measures a structure-to-electrolyte potential of -0.420 V CSE on
bare steel in aerated soil. When the cathodic protection system is energized, the potential shifts to -0.920
V CSE. Which polarization component contributes most significantly to this 500 mV shift?
A. Concentration polarization from hydroxide ion accumulation
B. Activation polarization at the cathodic surface
C. Ohmic drop through the soil electrolyte path
D. Resistance polarization from surface film formation
Correct Answer: B
Rationale: Activation polarization dominates at the cathode during cathodic protection because the hydrogen evolution
reaction requires an overpotential to drive the reaction. Concentration polarization (A) becomes significant only at high current
densities or in stagnant conditions, which are not described here.
Question 3
A zinc anode coupled to steel in seawater produces a measured current of 2.3 A. Over six months, the
current decays to 1.1 A while the steel potential remains protective. Which factor is the primary cause of
this current reduction?
A. Increased calcareous deposit formation on the steel cathode
B. Passivation of the zinc anode surface
C. Increased seawater temperature raising conductivity
D. Cathodic disbondment of the pipeline coating
Correct Answer: A
Rationale: Calcareous deposits (calcium and magnesium compounds) form on the cathodically protected steel surface,
increasing polarization resistance and reducing current demand. This is a normal and expected phenomenon in seawater CP
systems. Zinc anodes do not passivate (B) in seawater.
, Question 4
In a laboratory corrosion cell, a steel specimen shows a corrosion rate of 0.85 mm/year when the pH is
6.0. When the pH is raised to 9.5 with the same dissolved oxygen content, the corrosion rate drops to 0.12
mm/year. Which electrochemical principle explains this behavior?
A. Formation of a passive oxide film at higher pH
B. Decreased cathodic reaction kinetics in alkaline conditions
C. Reduced ionic conductivity of the electrolyte
D. Increased hydrogen evolution suppressing oxygen reduction
Correct Answer: A
Rationale: Steel forms a protective passive oxide film (magnetite) in alkaline environments, dramatically reducing corrosion
rates. While cathodic kinetics do change with pH, the primary mechanism for this magnitude of reduction is passivation.
Hydrogen evolution (D) is not significant in this pH range with oxygen present.
Question 5
A copper pipe connected to a galvanized steel water heater shows severe corrosion at the steel
connection after two years of service. The water conductivity is 450 µS/cm and temperature is 55°C.
Which factor most accelerates this galvanic corrosion?
A. The large cathode-to-anode area ratio favoring steel dissolution
B. The low conductivity water preventing current flow
C. The elevated temperature increasing exchange current density
D. The formation of a zinc hydroxide passive layer on the galvanized coating
Correct Answer: A
Rationale: Galvanic corrosion severity is directly proportional to the cathode-to-anode area ratio. Copper (noble cathode)
connected to zinc-coated steel (active anode) with a large copper surface area drives high current density at the steel
interface. Temperature (C) accelerates kinetics but area ratio is the dominant factor.
Question 6
A pipeline operator observes that corrosion rates increase significantly during summer months when soil
moisture content rises from 12% to 28%. The soil resistivity drops from 8,000 Ω·cm to 2,500 Ω·cm during
this period. Which relationship best describes this behavior?
A. Corrosion rate is inversely proportional to soil resistivity
B. Corrosion rate increases linearly with moisture content above 15%
C. Corrosion rate is independent of resistivity below 10,000 Ω·cm
D. Corrosion rate decreases as electrolyte conductivity improves
Correct Answer: A
Rationale: Lower soil resistivity indicates higher electrolyte conductivity, which facilitates ionic current flow between anodic and
cathodic sites, accelerating corrosion. The inverse relationship between corrosion rate and soil resistivity is well-established in
corrosion science.
