Minnesota Hydrogen Systems
Technician Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. What is the primary safety concern when handling hydrogen gas?
A. Color visibility
B. High toxicity
C. Flammability and wide explosive range
D. Radioactivity
Answer: C. Flammability and wide explosive range
Rationale: Hydrogen is extremely flammable and can form explosive
mixtures with air over a wide concentration range (4%–75%).
2. Hydrogen is most commonly stored in which form in industrial
systems?
A. Solid metal sheets
B. Liquid or compressed gas
, C. Plasma state
D. Gel suspension
Answer: B. Liquid or compressed gas
Rationale: Hydrogen is typically stored as compressed gas or
cryogenic liquid due to its low density.
3. What color is a standard hydrogen cylinder label?
A. Red
B. Green
C. Yellow
D. Blue
Answer: B. Green
Rationale: Hydrogen cylinders are typically labeled green for
identification in industrial safety systems.
4. What is the main byproduct of hydrogen combustion?
A. Carbon monoxide
B. Carbon dioxide
C. Water vapor
D. Nitrogen oxide
Answer: C. Water vapor
Rationale: Hydrogen combustion with oxygen produces only water
vapor as a byproduct.
,5. Hydrogen has which property compared to air?
A. Heavier
B. Same density
C. Lighter
D. Viscous
Answer: C. Lighter
Rationale: Hydrogen is significantly lighter than air, causing it to rise
rapidly when released.
6. Which material is most suitable for hydrogen piping systems?
A. Cast iron
B. Carbon steel (unprotected)
C. Stainless steel
D. Wood-lined pipes
Answer: C. Stainless steel
Rationale: Stainless steel resists hydrogen embrittlement better than
most materials.
7. What phenomenon causes metals to weaken in hydrogen
environments?
A. Oxidation
B. Corrosion fatigue
C. Hydrogen embrittlement
D. Thermal expansion
, Answer: C. Hydrogen embrittlement
Rationale: Hydrogen atoms diffuse into metals, making them brittle
and prone to cracking.
8. Hydrogen gas is odorized for leak detection in most systems.
A. True
B. False
Answer: B. False
Rationale: Hydrogen is colorless and odorless and is not typically
odorized due to contamination risks.
9. The ignition energy of hydrogen compared to gasoline is:
A. Higher
B. Lower
C. Equal
D. Not measurable
Answer: B. Lower
Rationale: Hydrogen requires very little energy to ignite, making it
highly sensitive to ignition sources.
10. What device is commonly used to detect hydrogen leaks?
A. Thermometer
B. Hydrogen sensor
C. Barometer
D. Hygrometer
Technician Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary safety concern when handling hydrogen gas?
A. Color visibility
B. High toxicity
C. Flammability and wide explosive range
D. Radioactivity
Answer: C. Flammability and wide explosive range
Rationale: Hydrogen is extremely flammable and can form explosive
mixtures with air over a wide concentration range (4%–75%).
2. Hydrogen is most commonly stored in which form in industrial
systems?
A. Solid metal sheets
B. Liquid or compressed gas
, C. Plasma state
D. Gel suspension
Answer: B. Liquid or compressed gas
Rationale: Hydrogen is typically stored as compressed gas or
cryogenic liquid due to its low density.
3. What color is a standard hydrogen cylinder label?
A. Red
B. Green
C. Yellow
D. Blue
Answer: B. Green
Rationale: Hydrogen cylinders are typically labeled green for
identification in industrial safety systems.
4. What is the main byproduct of hydrogen combustion?
A. Carbon monoxide
B. Carbon dioxide
C. Water vapor
D. Nitrogen oxide
Answer: C. Water vapor
Rationale: Hydrogen combustion with oxygen produces only water
vapor as a byproduct.
,5. Hydrogen has which property compared to air?
A. Heavier
B. Same density
C. Lighter
D. Viscous
Answer: C. Lighter
Rationale: Hydrogen is significantly lighter than air, causing it to rise
rapidly when released.
6. Which material is most suitable for hydrogen piping systems?
A. Cast iron
B. Carbon steel (unprotected)
C. Stainless steel
D. Wood-lined pipes
Answer: C. Stainless steel
Rationale: Stainless steel resists hydrogen embrittlement better than
most materials.
7. What phenomenon causes metals to weaken in hydrogen
environments?
A. Oxidation
B. Corrosion fatigue
C. Hydrogen embrittlement
D. Thermal expansion
, Answer: C. Hydrogen embrittlement
Rationale: Hydrogen atoms diffuse into metals, making them brittle
and prone to cracking.
8. Hydrogen gas is odorized for leak detection in most systems.
A. True
B. False
Answer: B. False
Rationale: Hydrogen is colorless and odorless and is not typically
odorized due to contamination risks.
9. The ignition energy of hydrogen compared to gasoline is:
A. Higher
B. Lower
C. Equal
D. Not measurable
Answer: B. Lower
Rationale: Hydrogen requires very little energy to ignite, making it
highly sensitive to ignition sources.
10. What device is commonly used to detect hydrogen leaks?
A. Thermometer
B. Hydrogen sensor
C. Barometer
D. Hygrometer
