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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 resis<vity D Metal loss or corrosion occurs at the A) cathode B) anode C) electronic path D) metallic path B What are the four parts of the corrosion cell A) anode, resistor, electrolyte, metallic path B) anode, cathode, electron, electronic path C) anode, cathode, electrolyte, metallic path C
NACE CP2 – EXAM QUESTIONS
& VERIFIED SOLUTIONS
(LATEST UPDATE 2024/2025)
True or False (t or f): Ions exist only in the electrolyte? 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 C At the cathodic surface in a corrosion cell, the electrons from the ____ meet ____ ions from the solu<on. A) cathode, hydrogen B) cathode, OH- C) anode, hydrogen D) anode, OH- C Oxida<on of the metal occurs at the ____ surfaces and reduc<on 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 A
F
The ________ represents the reversible work to move a unit charge from the electrode surface through the solu<on to the reference electrode A) current poten<al B) electrode poten<al C) resistance poten<al D) ohms poten<al E) Faraday poten<al B Metals occur in nature in the form of various chemical compounds referred to as
A) ores B) anodic metals C) cathodic metals D) carbohydrates A The amount of energy required by a metal during the refining process determines the ___ or _______ of the metal. A) current, ac<ve state B) voltage, ac<ve state C) ac<ve resistance, voltage
D) resistance, ac<ve state E) current, ac<ve resistance B During the refining stage of metal the ____ the energy, the more ____ the metal and the more tendency it has to corrode. A) higher, inac<ve B) lower, ac<ve C) higher, ac<ve D) lower, inac<ve C What is the most common iron ore? A) hemophite B) hema<te C) magnesium D) calcium E) aluminum B True or false Iron is considered thermodynamically unstable? T True or false Gold is more noble than zinc? T
A) current B) voltage C) resistance D) ohms E) siemens-cm A If a metallic path connects two electrodes inside an electrolyte, the ____ difference will cause a ____ to flow between them A) current, voltage B) resistance, current C) resistance, voltage D) voltage, current E) current, resistance D The more useful method of organizing metals in order of their tendency to corrode is _____ A) emf series B) pgp series C) nuclear series D) electron series E) galvanic series E The ____ expresses the exact electromo<ve force of a cell in terms of the ac<vi<es of products and reactants of the cell
A) Ernest Equa<on B) Faraday Equa<on C) Ohm's Law Equa<on D) Nernst Equa<on E) Uniform Equa<on D Given the Nernst Equa<on, using the Valence of Common Metals Table, and using the par<al Standard emf Series of Metals solve: What is the poten<al of zinc in a 0.01 molar zinc chloride solu<on at 25C? A) - 0.892V B) - 0.287V C) - 0.827V D) - 0.297V E) - 0.889V C E= - 0.763 + (0.059/2) log (0.71 0.01/1) = - 0.827V
A) lower, anode B) higher, cathode C) lower, cathode D) higher, anode D During metal fabrica<on of structures, highly stressed areas of a metal will tend to be at ____ energy levels, thus more ____ than less stressed areas A) higher, ac<ve B) lower, ac<ve C) higher, inac<ve D) lower, inac<ve A True or False (t or f): Corrosion cells may form because of differences in the electrolyte T ____ cells are responsible for much of the corrosion that take place in soils, par<cularly in bare or poorly coated pipe A) concentra<on B) steady state C) carbon D) dynamic E) telluric A
In many cases in naturally occurring soils, a por<on of pipe lying in the more _____ soil is the ____ and in the less ____soil is the ___. A) induc<ve, anode / induc<ve, cathode B) induc<ve, cathode / induc<ve, anode C) conduc<ve, anode / conduc<ve, cathode D) conduc<ve, cathode /conduc<ve, anode C The two most common types of concentra<on cells involved in promo<ng corrosion are ____ and ____. A) oxygen, nonmefalic ion B) oxygen, calcium C) lack of oxygen, metal ion D) oxygen, metal ion D What is the most common of the cathodic depolarizers, that can maintain and promote a cathodic reac<on? A) CO B) oxygen C) carbon D) OH- E) Hydrogen B Most corrosion on pipelines is on the ____ por<on of the pipe
C) 20
D) 70
E) 60
E
The corrosion poten<al of a metal might be - 500mv in an environment with a ph of 7, but the corrosion poten<al might be ____ at a ph of 8? A) - 440mv B) - 660mv C) - 300mv D) - 560mv D True or false (t or f) an acidic ph can be harmful to concrete, such as reinforced concrete structures? T A ph of less than ____ is considered to be harmful to concrete? A) 4 B) 6 C) 5 D) 2 E) 8 C The rate of corrosion is directly ____ to ____ flow?
A) inproporinate, current B) inproporinate, voltage C) propor<onal, voltage D) propor<onal, current D If a 1 Amp CP system must last 40 years and the electrochemical equivalent for silicon chromium cast iron anodes is 0.75 lb/A-yr, how many pounds of anodes are needed? A) 50lbs B) 35lbs C) 25 lbs D) 45lbs E) 30lbs E All things being equal, the greater the magnitude of the difference between two voltages of metals, the ____ the current flow and rate of corrosion A) higher B) lower A True or False ( t or f) Magnesium will corrode at a slower rate when connected to steel rather than zinc? F
B) Ag/agci C) Calomel D) Zinc E) SHE B Which reference electrode is mostly commonly used in concrete structures? A) CSE B) Ag/agci C) Calomel D) Zinc E) SHE B Which of the following is primarily a laboratory electrode? A) CSE B) Ag/agci C) Calomel D) Zinc C When doing a structure to electrolyte poten<al , the structure is connected via the _____ terminal and the reference is connected via the _____ terminal A) nega<ve , posi<ve B) posi<ve, nega<ve B
A poten<al of - 0.810Vcse converted to Calomel (SCE) A) +0.306 sce B) - 0.750 sce C) - 0.735 sce C A poten<al of - 0.810Vcse converted to Ag/agci (SSC) A) +0.306 ssc B) - 0.735 ssc C) - 0.750 ssc C A poten<al of - 0.810Vcse converted to Zinc (ZRE) A) +0.306 zre B) - 0.735 zre C) - 0.750 zre A True or False (t or f) The poten<al of a STATIONARY reference electrode should be checked from <me to <me with a portable reference electrode that is known to be accurate under "no current" condi<ons. T
The name for the current that exists during the steady state of polariza<on is called the _____ of the system A) telluric current B) dynamic current C) corrosion current D) mixed poten<al current E) closed current C The poten<al normally measured between the polarized cathode poten<al and the polarized anode poten<al A) mixed poten<al B) corrosion poten<al C) corrosion current D) open circuit poten<al A _____ are the poten<als of the cathode and anode when the corrosion current is zero A) mixed poten<als B) corrosion poten<als C) corrosion current poten<als D) open circuit poten<als D ______ is the result of the reac<on steps at the structure/electrolyte interface including the actual transfer of charge
A) ac<va<on polariza<on B) concentra<on polariza<on C) mixed polariza<on D) reactant polariza<on A In concentrated acids, _______ polariza<on predominates A) ac<va<on polariza<on B) concentra<on polariza<on C) mixed polariza<on D) reactant polariza<on A _______ is the result of reac<on steps involving the diffusion of reactants up to the reac<on products away from the reac<on surface A) ac<va<on polariza<on B) concentra<on polariza<on C) mixed polariza<on D) reactant polariza<on B Anything that causes a deple<on of available reactants or a buildup of reac<on products results in a ____ in the reac<on rate and an _____ in concentra<on polariza<on. A) decrease, increase B) increase, decrease
