All Free Chemical Engineering MCQs with Answers

• A. Platinum
• B. Cobalt
• C. Vanadium
• D. Nickel

Explanation: Platinum is a highly active oxidation catalyst in automobile catalytic converters, promoting conversion of CO to CO₂ and oxidation of…

• A. y = k1 ln (k2t + k3)
• B. y2 = 2k1t + k2
• C. y = k1 t + k2
• D. y = k1t3 + k2

Explanation: A parabolic oxidation law means the square of film thickness increases linearly with time, giving y² = 2k₁t + k₂ in the notation used.

• A. Sec-1. mole°
• B. Moles1. sec-1
• C. Moles-1. sec1
• D. Moles1. sec1

Explanation: For a second-order rate law, rate = kC², so k = rate/C². Its units are concentration⁻¹ time⁻¹, commonly L mol⁻¹ s⁻¹, matching option c…

• A. 13.6 cms of Hg
• B. 13.6 metres of Hg
• C. 1 metre of H2O
• D. 34 ft ofH2O

Explanation: One atmosphere equals 760 mm Hg, which is approximately 10.3 m or 34 ft of water. Therefore, 34 ft of H2O is the matching hydrostatic head.

• A. Centipoise
• B. Poise
• C. Stoke
• D. Both B. & C.

Explanation: Dynamic viscosity of water near room temperature is approximately 1 centipoise, equal to 0.001 Pa·s.

• A. kg/m.hr
• B. kg/m2.hr
• C. kg/hr
• D. kg/m2

Explanation: Mass velocity is mass flow rate per unit cross-sectional area, so its dimensions are mass/(area·time).

• A. cm2/second
• B. Stoke
• C. Poise
• D. None of these

Explanation: Kinematic viscosity has units of area per time, such as stoke or cm²/s.

• A. Decreases
• B. Increases
• C. Remain constant
• D. Increases linearly

Explanation: Heating increases molecular motion and weakens the cohesive effect responsible for surface tension at the liquid surface.

• A. In which there is a temperature drop
• B. Which can be performed in a pipe with a constriction
• C. Which is exemplified by a non-steady flow expansion
• D. In which there is an increase in temperature

Explanation: Throttling through a valve or pipe constriction is an adiabatic steady-flow process with negligible changes in kinetic and potential…

• A. Bag filter
• B. Cyclone separator
• C. Dust catcher (gravity type)
• D. Hollow wet scrubber

Explanation: A gravity dust catcher relies mainly on low gas velocity and settling, so it cannot effectively remove very small particles.

• A. Reynold stresses
• B. Shear forces
• C. Neither A. nor B.
• D. Both A. & B.

Explanation: Turbulent valve flow generates fluctuating Reynolds stresses and strong shear forces, which produce pressure fluctuations and aerodynamic…

• A. Centrifugal force on
• B. Diffusion of
• C. Gravitational force on
• D. Electrostatic force on

Explanation: A cyclone separator spins the gas-solid mixture, forcing denser dust particles outward by centrifugal force so they fall along the wall.

• A. Diameter
• B. All A., B. & C.
• C. Overall height
• D. Inlet gas velocity

Explanation: Cyclone performance is affected by particle settling conditions, which depend on cyclone diameter, inlet gas velocity and geometry such as…

• A. Pipe vibrations
• B. Fluctuation in liquid flow
• C. Boundary layer separation
• D. Cavitation

Explanation: Cavitation produces bubbles that form and collapse rapidly, creating strong pressure pulses and noise in flowing liquids.

• A. Wet scrubber
• B. Bag filter
• C. Dust catcher
• D. Electrostatic precipitators

Explanation: Electrostatic precipitators impart charge to fine particles and collect them on oppositely charged plates, making them effective for the…

• A. Electrostatic precipitator
• B. Gravity settling chamber
• C. Packed scrubber
• D. Hydrocyclone

Explanation: An electrostatic precipitator can remove very fine, submicronic particles by electrically charging them and collecting them on oppositely…

• A. It is a line across which there is no flow and it is equivalent to a rigid boundary
• B. It is always parallel to the main direction of the fluid flow
• C. Streamlines intersect at isolated point of zero velocity and infinite velocity
• D. The fluid lying between any two streamlines can be considered to be in isolation and the
• E. streamline spacing varies inversely as the velocity

Explanation: A streamline is tangent to the local fluid velocity, not necessarily parallel to one fixed overall or main flow direction, so statement A…

• A. Venturimeter occupies less space than an orificemeter
• B. leaving the Venturimeter
• C. Discharge of fluid through a Venturimeter depends upon the gage difference irrespective of
• D. the orientation of Venturimeter
• E. For frictionless flow, the fluid pressure entering the venturi meter will be exactly equal to that
• F. Venturimeter incurs less power loss compared to an equivalent orificemeter

Explanation: A Venturimeter has a converging section, throat, and diverging section, so it is considerably longer and bulkier than an orifice plate.

• A. The value of Mach number is always unity at the throat
• B. direction
• C. Throughout the converging portion of the tube, the density increases in the downstream
• D. No shock wave develops in the tube when the Mach number at exit is greater than unity
• E. None of these

Explanation: Mach number equals unity at the throat only when the nozzle is choked, not in every case.

• A. Platinum
• B. Copper
• C. Constantan
• D. Chromium

Explanation: A hot-wire anemometer uses a fine electrically heated wire whose cooling indicates gas velocity; platinum is preferred because it is…