TEXAS PROFESSIONAL ENGINEER
CHEMICAL ENGINEERING LICENSING EXAM
ACTUAL 2026 VERIFIED QUESTIONS WITH
ANSWERS COMPREHENSIVE &
RATIONALE|INSTANT DOWNLOAD
1. A chemical engineer designing a distillation column wants to
determine the minimum number of theoretical stages required for a
binary separation. Which method is most appropriate for estimating
this value under total reflux conditions?
A. McCabe-Thiele graphical method
B. Fenske equation
C. Underwood equations
D. Rayleigh distillation equation
Answer: B. Fenske equation
Rationale: The Fenske equation calculates the minimum number of
theoretical stages required for a multicomponent or binary distillation
system at total reflux. The McCabe-Thiele method determines actual
stages at specified operating conditions, Underwood equations
determine minimum reflux ratio, and Rayleigh equations apply to
differential batch distillation.
2. A chemical processing facility experiences increased pressure
drop across a packed absorption column. Which condition is the
most likely cause?
A. Reduced gas flow rate
B. Decreased liquid viscosity
1
,C. Excessive flooding
D. Reduced packing height
Answer: C. Excessive flooding
Rationale: Flooding occurs when liquid accumulation prevents proper
gas flow, causing a sharp increase in pressure drop. Lower gas rates
and reduced viscosity generally decrease pressure losses, while
packing height affects total capacity rather than sudden pressure
increases.
3. For an ideal plug flow reactor (PFR) carrying out a first-order
reaction, increasing reactor volume while maintaining constant flow
rate will:
A. Decrease conversion
B. Increase conversion
C. Have no effect
D. Increase reaction temperature only
Answer: B. Increase conversion
Rationale: In a plug flow reactor, increased residence time allows
more reactant molecules to undergo reaction. For first-order
reactions, conversion increases exponentially with increasing
residence time according to the design equation.
4. The primary purpose of using a catalyst in an industrial chemical
reaction is to:
A. Increase equilibrium conversion
B. Change reaction enthalpy
C. Lower activation energy
D. Increase reactant concentration
2
,Answer: C. Lower activation energy
Rationale: Catalysts increase reaction rates by lowering activation
energy while remaining chemically unchanged. They do not alter
equilibrium constants, reaction heat, or final equilibrium conversion.
5. A heat exchanger has hot fluid entering at 200°C and leaving at
100°C. The cold fluid enters at 50°C and exits at 120°C. Which
temperature difference method is commonly used for
countercurrent heat exchanger design?
A. Arithmetic average temperature difference
B. Log mean temperature difference
C. Maximum temperature difference
D. Heat capacity difference method
Answer: B. Log mean temperature difference
Rationale: The log mean temperature difference (LMTD) provides the
correct average temperature driving force for heat exchanger design
when temperatures change along the exchanger length.
6. In chemical process safety, the main objective of a Hazard and
Operability Study (HAZOP) is to:
A. Calculate equipment cost
B. Identify process deviations and hazards
C. Determine product quality specifications
D. Optimize energy consumption only
Answer: B. Identify process deviations and hazards
Rationale: HAZOP systematically examines process parameters using
guide words such as "more," "less," and "reverse" to identify possible
deviations that could create safety risks.
3
, 7. According to the Arrhenius equation, increasing temperature
generally causes:
A. Decreased reaction rate constant
B. Increased reaction rate constant
C. No change in reaction rate
D. Decreased activation energy
Answer: B. Increased reaction rate constant
Rationale: The Arrhenius relationship shows that higher temperature
increases the fraction of molecules exceeding activation energy,
resulting in a larger rate constant.
8. A chemical engineer selects stainless steel for a reactor handling
corrosive chemicals primarily because stainless steel provides:
A. Maximum electrical conductivity
B. Corrosion resistance
C. Lowest material cost
D. Highest thermal insulation
Answer: B. Corrosion resistance
Rationale: Stainless steel contains chromium that forms a passive
oxide layer, providing resistance against many corrosive environments
encountered in chemical processing.
9. The Reynolds number is used in fluid mechanics to determine:
A. Heat transfer coefficient
B. Flow regime
4
CHEMICAL ENGINEERING LICENSING EXAM
ACTUAL 2026 VERIFIED QUESTIONS WITH
ANSWERS COMPREHENSIVE &
RATIONALE|INSTANT DOWNLOAD
1. A chemical engineer designing a distillation column wants to
determine the minimum number of theoretical stages required for a
binary separation. Which method is most appropriate for estimating
this value under total reflux conditions?
A. McCabe-Thiele graphical method
B. Fenske equation
C. Underwood equations
D. Rayleigh distillation equation
Answer: B. Fenske equation
Rationale: The Fenske equation calculates the minimum number of
theoretical stages required for a multicomponent or binary distillation
system at total reflux. The McCabe-Thiele method determines actual
stages at specified operating conditions, Underwood equations
determine minimum reflux ratio, and Rayleigh equations apply to
differential batch distillation.
2. A chemical processing facility experiences increased pressure
drop across a packed absorption column. Which condition is the
most likely cause?
A. Reduced gas flow rate
B. Decreased liquid viscosity
1
,C. Excessive flooding
D. Reduced packing height
Answer: C. Excessive flooding
Rationale: Flooding occurs when liquid accumulation prevents proper
gas flow, causing a sharp increase in pressure drop. Lower gas rates
and reduced viscosity generally decrease pressure losses, while
packing height affects total capacity rather than sudden pressure
increases.
3. For an ideal plug flow reactor (PFR) carrying out a first-order
reaction, increasing reactor volume while maintaining constant flow
rate will:
A. Decrease conversion
B. Increase conversion
C. Have no effect
D. Increase reaction temperature only
Answer: B. Increase conversion
Rationale: In a plug flow reactor, increased residence time allows
more reactant molecules to undergo reaction. For first-order
reactions, conversion increases exponentially with increasing
residence time according to the design equation.
4. The primary purpose of using a catalyst in an industrial chemical
reaction is to:
A. Increase equilibrium conversion
B. Change reaction enthalpy
C. Lower activation energy
D. Increase reactant concentration
2
,Answer: C. Lower activation energy
Rationale: Catalysts increase reaction rates by lowering activation
energy while remaining chemically unchanged. They do not alter
equilibrium constants, reaction heat, or final equilibrium conversion.
5. A heat exchanger has hot fluid entering at 200°C and leaving at
100°C. The cold fluid enters at 50°C and exits at 120°C. Which
temperature difference method is commonly used for
countercurrent heat exchanger design?
A. Arithmetic average temperature difference
B. Log mean temperature difference
C. Maximum temperature difference
D. Heat capacity difference method
Answer: B. Log mean temperature difference
Rationale: The log mean temperature difference (LMTD) provides the
correct average temperature driving force for heat exchanger design
when temperatures change along the exchanger length.
6. In chemical process safety, the main objective of a Hazard and
Operability Study (HAZOP) is to:
A. Calculate equipment cost
B. Identify process deviations and hazards
C. Determine product quality specifications
D. Optimize energy consumption only
Answer: B. Identify process deviations and hazards
Rationale: HAZOP systematically examines process parameters using
guide words such as "more," "less," and "reverse" to identify possible
deviations that could create safety risks.
3
, 7. According to the Arrhenius equation, increasing temperature
generally causes:
A. Decreased reaction rate constant
B. Increased reaction rate constant
C. No change in reaction rate
D. Decreased activation energy
Answer: B. Increased reaction rate constant
Rationale: The Arrhenius relationship shows that higher temperature
increases the fraction of molecules exceeding activation energy,
resulting in a larger rate constant.
8. A chemical engineer selects stainless steel for a reactor handling
corrosive chemicals primarily because stainless steel provides:
A. Maximum electrical conductivity
B. Corrosion resistance
C. Lowest material cost
D. Highest thermal insulation
Answer: B. Corrosion resistance
Rationale: Stainless steel contains chromium that forms a passive
oxide layer, providing resistance against many corrosive environments
encountered in chemical processing.
9. The Reynolds number is used in fluid mechanics to determine:
A. Heat transfer coefficient
B. Flow regime
4
