Free Internal Corrosion Specialist Exam Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Internal Corrosion Specialist Exam practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1At an actively corroding region of a steel pipe in an aqueous electrolyte, iron atoms lose electrons and enter solution as positive ions. How should this region be classified?

   1. A. A cathode supporting oxidation
   2. B. An anode supporting oxidation
   3. C. A cathode supporting reduction
   4. D. An anode supporting reduction

   Answer: B

   Explanation: The handbook states, "The metal atoms release electrons (are oxidized) and become positive ions. The site at which this occurs is known as the anode." Thus the observed iron dissolution is anodic oxidation; reduction consumes electrons at cathodic sites.

   Reference: DOE Fundamentals Handbook: Chemistry, Volume 1 of 2 — CH-02, p.5, Oxidation-Reduction Reactions

2. 2Water condenses from CO₂- and H₂S-containing gas and collects against the steel at a pipeline low point. Why does this change establish an internal-corrosion concern?

   1. A. Condensation separates the acidic gases completely from the aqueous phase.
   2. B. The condensed water provides an electrolyte in which acidic gas species can act on steel.
   3. C. The gas species attack steel only while all water remains in the vapor phase.
   4. D. Dissolving the acidic gas species raises pH and reduces the water’s acidity.

   Answer: B

   Explanation: The report states, "If the water condenses, it can react with the carbon dioxide or hydrogen sulfide to form an acid that might collect in a low spot and cause internal corrosion." Condensation provides an aqueous exposure at the steel; it neither guarantees complete gas removal nor isolates the pooled water from the pipe.

   Reference: Pipeline Corrosion: Final Report to PHMSA — §3.4.1, p.22, Gas Pipelines

3. 3What function does triethylene glycol perform in a liquid-desiccant natural-gas dehydrator?

   1. A. It removes moisture solely by gravity settling of entrained droplets.
   2. B. It adsorbs water on the fixed surface of a solid TEG bed.
   3. C. It acts as a liquid desiccant that takes up water from the gas.
   4. D. It reacts with CO₂ as an acid-gas absorbent instead of removing water.

   Answer: C

   Explanation: EPA describes "triethylene glycol (TEG) as the desiccant agent to remove water from the natural gas stream." In this liquid-desiccant system, TEG takes up water. Gravity droplet separation, solid-bed adsorption, and acid-gas absorption describe different treatment mechanisms.

   Reference: EPA Natural Gas STAR: Optimize Glycol Circulation — Summary, opening sentence

4. 4Why does a conventional ER corrosion probe use a protected reference element along with the exposed measurement element?

   1. A. To make reference-element corrosion cancel exposed-element corrosion
   2. B. To compensate temperature-dependent resistivity using the element resistance ratio
   3. C. To keep the reference resistance constant despite changes in its temperature
   4. D. To use only an initial reference reading without tracking subsequent temperature effects

   Answer: B

   Explanation: Cosasco states that the resistance ratio provides "automatic compensation for temperature changes." Both elements respond to temperature, while the reference is protected from corrosion. The reference is not intended to corrode at the exposed rate, remain temperature-independent, or supply only an unchanging initial correction.

   Reference: Cosasco Electrical Resistance (ER) Probe Selection Guide — p.1, temperature compensation description

5. 5Under 49 CFR §195.579(b)(3), a hazardous-liquid operator uses monitoring equipment to evaluate corrosion inhibitors. What is the longest permitted interval between examinations, while also meeting the calendar-year frequency requirement?

   1. A. 6 months, at least once each calendar year
   2. B. 8 months, at least twice each calendar year
   3. C. 12 months, at least once each calendar year
   4. D. 7½ months, at least twice each calendar year

   Answer: D

   Explanation: The rule requires examinations "at least twice each calendar year, but with intervals not exceeding 71⁄2 months." Both limits apply. A shorter interval does not replace the twice-per-calendar-year requirement, and an eight- or twelve-month interval exceeds the maximum.

   Reference: 49 CFR §195.579 — Mitigating Internal Corrosion — §195.579(b)(3)

6. 6Two electrodes made from the same metal contact regions of an electrolyte having different concentrations. Which statement correctly describes this electrochemical arrangement?

   1. A. A cell potential requires the two electrodes to be different metals.
   2. B. A cell potential requires unequal electrode areas rather than different concentrations.
   3. C. A concentration cell can develop despite the identical electrode materials.
   4. D. Matching electrode materials ensure zero potential despite the concentration difference.

   Answer: C

   Explanation: The handbook defines "concentration cells (cells containing electrodes of the same substance under different conditions of concentration)." Different solution concentrations can therefore establish the cell even when the electrode materials match; dissimilar metals and unequal areas are not required.

   Reference: DOE Fundamentals Handbook: Chemistry, Volume 1 of 2 — CH-02, p.3, Electrochemical Cells

7. 7A gas-line separator removes entrained liquid droplets, but the downstream gas can cool below its water dew point. Which conclusion is justified when assessing future internal-corrosion conditions?

   1. A. It removes entrained droplets and also removes essentially all remaining water vapor.
   2. B. It lowers the gas dew point in direct proportion to the volume of liquid drained.
   3. C. It prevents new condensation until its liquid-storage capacity has been reached.
   4. D. It removes entrained liquid but can leave water vapor that condenses after further cooling.

   Answer: D

   Explanation: The report states, "However, physical methods cannot significantly reduce the dew point, so periodic upsets can occur." A droplet separator does not act as a vapor desiccant. Liquid drainage or storage capacity does not establish a lower vapor dew point or prevent new downstream condensation.

   Reference: Pipeline Corrosion: Final Report to PHMSA — §3.4.3.1, p.23, Dehydration

8. 8Water-loaded TEG leaves a gas-dehydration contactor. Which process restores it for reuse in the contactor?

   1. A. Heat the loaded TEG to remove absorbed water.
   2. B. Cool the loaded TEG while retaining its absorbed water.
   3. C. Recycle the loaded TEG without separating any water.
   4. D. Blend the loaded TEG with additional untreated water.

   Answer: A

   Explanation: The technical description states, "The water laden TEG is circulated in a closed system, where the water is boiled from the TEG. The regenerated TEG then is recirculated to the contacting tower." Regeneration removes the absorbed water before reuse; retaining or adding water does not restore drying capacity.

   Reference: P C McKenzie: Dehydration of Natural Gas — Dehydration of Natural Gas, final process paragraph

9. 9A monitoring program needs rapid detection of changes at a low anticipated general corrosion rate. What tradeoff accompanies a more sensitive ER probe element?

   1. A. A slower response and a longer consumable-element life
   2. B. A slower response and a shorter consumable-element life
   3. C. A faster response and a shorter consumable-element life
   4. D. A faster response and a longer consumable-element life

   Answer: C

   Explanation: Cosasco states, "A sensitive probe will respond more quickly to process upsets than one with a greater span, but the element will corrode away and require replacement more quickly." Increased sensitivity therefore trades faster response for shorter element life.

   Reference: Cosasco Electrical Resistance (ER) Probe Selection Guide — p.4, Probe Sensitivity Selection

10. 10A Part 195 operator removes pipe and finds internal corrosion requiring corrective action under §195.585. Under §195.579(c), what further investigation is required around the removal?

    1. A. Investigate both circumferentially and longitudinally beyond the removed pipe.
    2. B. Investigate longitudinally beyond the removal but omit circumferential extent.
    3. C. Investigate the circumference within the removed length but not beyond that length.
    4. D. Inspect the removed pipe’s internal surface without investigating adjacent pipe.

    Answer: A

    Explanation: Section 195.579(c) requires the operator to "investigate circumferentially and longitudinally beyond the removed pipe". Both directions and extension beyond the removed length are required to determine whether additional nearby corrosion needs remedial action.

    Reference: 49 CFR §195.579 — Mitigating Internal Corrosion — §195.579(c), Removing pipe