(CP1) Exam 2026/2027 Questions
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Questions And Correct Verified Solutions
With Detailed Rationales (100% Correct
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Question 1:
What is corrosion?
A. Mechanical wear on a metal surface
B. The electrochemical deterioration of a material due to reaction with its environment
C. Plastic deformation under load
D. The application of protective coatings
Correct Answer: B. The electrochemical deterioration of a material due to reaction
with its environment
Rationale: Corrosion is the deterioration of a substance, usually a metal, from a reaction
with its environment. It commonly occurs through electrochemical reactions between
the metal and its environment. This process involves electron transfer and requires
specific conditions to occur.
Question 2:
Which of the following is NOT a required component of an electrochemical corrosion
cell?
A. Anode
B. Cathode
,C. Electrolyte
D. External power source
Correct Answer: D. External power source
Rationale: The four essential components of a corrosion cell are: anode (where
oxidation occurs), cathode (where reduction occurs), electrolyte (conductive medium),
and metallic path (electrical connection). An external power source is not required for a
galvanic corrosion cell; it is only needed for impressed current CP systems.
Question 3:
What is the fundamental electrochemical principle by which cathodic protection stops
corrosion?
A. The protected structure becomes the anode, attracting all corrosive ions
B. The protected structure becomes the cathode, preventing anodic dissolution
C. A protective oxide layer forms on the metal surface
D. The electrolyte is completely removed from around the structure
Correct Answer: B. The protected structure becomes the cathode, preventing
anodic dissolution
Rationale: Cathodic protection works by making the protected structure the cathode of
an electrochemical cell, thereby preventing the anodic (oxidation) reaction that causes
metal loss. This shifts the potential of the structure into the immune region. The
technique reduces corrosion of a metal surface by making that surface the cathode of
an electrochemical cell.
Question 4:
In a galvanic corrosion cell, the more active metal will become the:
A. Cathode
B. Anode
,C. Electrolyte
D. Neither A nor B
Correct Answer: B. Anode
Rationale: The anode is the electrode at which oxidation occurs, and electrons flow
away from the anode in the external circuit. In a galvanic cell, the more active metal
becomes the anode and corrodes, while the more noble metal becomes the cathode.
Corrosion usually occurs and metal ions enter the solution at the anode.
Question 5:
The oxidation reaction that occurs at the anode involves:
A. Gain of electrons
B. Loss of electrons
C. Gain of protons
D. Loss of protons
Correct Answer: B. Loss of electrons
Rationale: The anode is the site of oxidation, where the metal loses electrons and
corrodes. Electrons flow away from the anode in the external circuit. This loss of
electrons is the fundamental anodic reaction that causes metal deterioration.
Question 6:
The reduction reaction that occurs at the cathode involves:
A. Gain of electrons
B. Loss of electrons
C. Gain of protons
D. Loss of protons
Correct Answer: A. Gain of electrons
, Rationale: The cathode is the electrode at which reduction is the principal reaction, and
electrons flow towards the cathode in the external circuit. Reduction involves the gain of
electrons, which is why the cathode is protected from corrosion.
Question 7:
The galvanic series ranks metals by their:
A. Weight
B. Electrochemical potential (nobility)
C. Electrical conductivity
D. Thermal conductivity
Correct Answer: B. Electrochemical potential (nobility)
Rationale: The galvanic series is a listing of metals in order of reactivity (more or less
noble) in seawater at 25°C. Metals at the anodic (active) end are more prone to
corrosion, while metals at the cathodic (noble) end are more resistant.
Question 8:
Which of the following is a common sacrificial anode material?
A. Copper
B. Magnesium
C. Stainless steel
D. Graphite only
Correct Answer: B. Magnesium
Rationale: Magnesium is widely used as a sacrificial anode because it is more active
than steel and corrodes preferentially. It provides high driving voltage suitable for
resistive soils. Zinc is also used in some applications.