For a reverse osmosis process, the concentration polarization effect results in:

The correct answer is A: Higher salt concentration at membrane surface than in bulk solution. Due to higher solute rejection, solutes accumulate near membrane surface, increasing local osmotic pressure and reducing driving force.

What is the activation energy for a reaction if its rate constant doubles when temperature increases from 300K to 310K?

The correct answer is B: 52.8 kJ/mol. Using Arrhenius equation: ln(k₂/k₁) = (Eₐ/R)[1/T₁ - 1/T₂]; ln(2) = (Eₐ/8.314)[1/300 - 1/310]; Eₐ ≈ 52.8 kJ/mol

In a settling tank (clarifier) with depth H = 2 m, overflow rate = 1 m³/m²·h, and settling velocity of particles = 0.02 m/min, will the particles settle completely?

The correct answer is A: Yes, settling velocity is much higher. Settling velocity = 0.02 m/min = 1.2 m/h. Overflow rate = 1 m³/m²·h means rise velocity = 1 m/h < 1.2 m/h, so particles will settle

In industrial practice, which method is most effective for controlling selectivity toward desired product in competitive parallel reactions?

The correct answer is C: Maintaining low concentrations of undesired reactant through controlled feeding. For parallel reactions with different orders, maintaining low concentrations of reactants involved in undesired paths (particularly for higher-order undesired reactions) improves selectivity toward desired product.

For a zero-order reaction, the integrated rate law is:

The correct answer is A: [A] = [A]₀ - kt. Zero-order integrated rate law: [A] = [A]₀ - kt, linear with time

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Chemical Engineering
Fluid Mechanics

Process design, thermodynamics, reactions

33 Q 5 Topics Take Mock Test

Difficulty: All Easy Medium Hard 21–30 of 33

Topics in Chemical Engineering

All Mass Transfer 100 Heat Transfer 100 Fluid Mechanics 100 Chemical Reaction Engineering 100 Thermodynamics 97

Q.21 Easy Fluid Mechanics

Which of the following pump types operates on the principle of positive displacement with rotating screws?

A Centrifugal pump

B Reciprocating pump

C Screw pump

D Jet pump

Correct Answer: C. Screw pump

EXPLANATION

Screw pumps (Archimedean screw or progressive cavity pumps) use rotating screws for positive displacement. They are used for high viscosity fluids.

Test

Q.22 Easy Fluid Mechanics

Which dimensionless number is used to characterize the ratio of inertial forces to viscous forces in fluid flow?

A Froude number

B Reynolds number

C Mach number

D Strouhal number

Correct Answer: B. Reynolds number

EXPLANATION

Reynolds number (Re = ρVD/μ) represents the ratio of inertial to viscous forces and determines the flow regime (laminar, transitional, or turbulent).

Test

Q.23 Easy Fluid Mechanics

For laminar flow of a viscous fluid between two parallel plates, the velocity profile is:

A Linear

B Parabolic

C Logarithmic

D Exponential

Correct Answer: B. Parabolic

EXPLANATION

For laminar flow between parallel plates (Poiseuille flow), the velocity profile is parabolic due to the balance between pressure gradient and viscous forces.

Test

Q.24 Easy Fluid Mechanics

A fluid with dynamic viscosity of 0.8 Pa·s and density of 900 kg/m³ flows through a circular pipe. What is the kinematic viscosity of this fluid?

A 8.89 × 10⁻⁴ m²/s

B 1.12 × 10⁻³ m²/s

C 720 m²/s

D 1.125 × 10⁻³ m²/s

Correct Answer: A. 8.89 × 10⁻⁴ m²/s

EXPLANATION

Kinematic viscosity ν = μ/ρ = 0.8/900 = 8.89 × 10⁻⁴ m²/s

Test

Q.25 Easy Fluid Mechanics

Which pumping principle is used in a gear pump?

A Dynamic principle (Bernoulli effect)

B Positive displacement principle

C Gravity principle

D Capillary action

Correct Answer: B. Positive displacement principle

EXPLANATION

Gear pumps are positive displacement pumps. They move fixed volumes of fluid per rotation. Dynamic principle applies to centrifugal pumps.

Test

Q.26 Easy Fluid Mechanics

In fluid mechanics, which dimensionless number represents the ratio of inertial forces to viscous forces?

A Reynolds number

B Froude number

C Weber number

D Mach number

Correct Answer: A. Reynolds number

EXPLANATION

Reynolds number Re = (Inertial forces)/(Viscous forces) = ρVD/μ. It characterizes flow regime (laminar vs turbulent).

Test

Q.27 Easy Fluid Mechanics

For a Newtonian fluid, shear stress (τ) is related to shear rate (dV/dy) by:

A τ = μ(dV/dy)

B τ = k(dV/dy)ⁿ

C τ = μ₀ + k(dV/dy)ⁿ

D τ proportional to (dV/dy)²

Correct Answer: A. τ = μ(dV/dy)

EXPLANATION

Newton's law of viscosity: τ = μ(dV/dy). Option B is power law (non-Newtonian), C is Bingham plastic model.

Test

Q.28 Easy Fluid Mechanics

A fluid with dynamic viscosity 0.5 Pa·s and density 800 kg/m³ flows in a pipe. Its kinematic viscosity is:

A 6.25×10⁻⁴ m²/s

B 6.25×10⁻³ m²/s

C 1.6×10⁻³ m²/s

D 2.5×10⁻³ m²/s

Correct Answer: A. 6.25×10⁻⁴ m²/s

EXPLANATION

ν = μ/ρ = 0.5/800 = 6.25×10⁻⁴ m²/s.

Test

Q.29 Easy Fluid Mechanics

In the Bernoulli equation, which term represents the pressure energy per unit volume?

A P/ρ

B ρgz

C P

D V²/2

Correct Answer: C. P

EXPLANATION

The Bernoulli equation is P + ½ρV² + ρgz = constant. P itself is pressure energy per unit volume (not P/ρ which is pressure head).

Test

Q.30 Easy Fluid Mechanics

A centrifugal pump operates at 1500 RPM. If the impeller diameter is 0.3 m, what is the tip speed?

A 23.56 m/s

B 47.12 m/s

C 11.78 m/s

D 35.34 m/s

Correct Answer: A. 23.56 m/s

EXPLANATION

Tip speed = πDN/60 = π × 0.3 × 1500/60 = 23.56 m/s (where N is in RPM).

Test

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