All Free Chemical Engineering MCQs with Answers

• A. Partially filled pipeline
• B. Pipe
• C. Open channel
• D. River

Explanation: A completely filled pipe carries pressure flow because the fluid is confined and its motion is driven by a pressure gradient.

• A. Tall narrow vessel
• B. Deep bed of solids
• C. Shallow beds of solids and proper choice of particle size
• D. Very large particles

Explanation: Slugging is reduced by using a shallow bed and selecting particles that fluidise uniformly, which limits the growth of large gas pockets.

• A. Disk
• B. Skin
• C. None of these
• D. Form

Explanation: Wakes form behind an immersed body when the flow separates, producing pressure or form drag.

• A. Inertial forces to viscous forces
• B. Viscous forces to gravity forces
• C. Viscous forces to inertial forces
• D. Inertial forces to gravity forces

Explanation: Reynolds number compares inertial forces with viscous forces, commonly written as Re = ρvD/μ.

• A. 0.93 to 0.98
• B. 0.58 to 0.8
• C. 0.2 to 0.3
• D. 0.02 to 0.03

Explanation: The discharge coefficient of a standard sharp-edged orifice plate is typically around 0.6, with a practical range close to 0.58 to 0.8…

• A. Velocity of fluid
• B. Size of pipe
• C. None of these
• D. Length of pipe and number of bends

Explanation: Pressure drop is affected by velocity, pipe size, length, and fittings such as bends.

• A. Hagen and Poiseuille
• B. Reynolds
• C. Pascal
• D. Blake-Plummer

Explanation: Hagen and Poiseuille experimentally established the relationship for laminar flow through a circular tube, now expressed in the…

• A. Water
• B. Any liquid
• C. Solids
• D. None of these

Explanation: A cock is a manually operated valve commonly used to start, stop, or regulate liquid flow.

• A. Wetted perimeter to flow area
• B. Flow area to square of wetted perimeter
• C. Flow area to wetted perimeter
• D. Square root of flow area to wetted perimeter

Explanation: Hydraulic radius is defined as flow cross-sectional area divided by wetted perimeter, R_h = A/P.

• A. Both B. and C.
• B. Speed of the impeller
• C. Diameter of the impeller
• D. Barometric pressure

Explanation: The maximum suction lift is fundamentally limited by atmospheric pressure, which supplies the pressure head pushing water up into the…

• A. 7
• B. 700
• C. 7000
• D. 630

Explanation: Using Re = VD/ν gives V = Reν/D = (2100)(0.01)/3 = 7 cm/s. The viscosity ratio is kinematic viscosity, so its given units can be used…

• A. Deliver liquid at uniform pressure
• B. Are not subject to air binding
• C. Can handle slurries more efficiently
• D. Can be operated with delivery valve closed

Explanation: A reciprocating pump is a positive-displacement pump and does not normally suffer from air binding in the same way as a centrifugal pump.

• A. 0.75 - 0.90
• B. 0.5 - 0.75
• C. 0.61 - 0.63
• D. 0.35 - 0.55

Explanation: A sharp-edged circular orifice has a discharge coefficient of about 0.61 to 0.63 for the stated beta range.

• A. Mechanical energy balance in boundary layer
• B. Kinetic energy balance in laminar flow
• C. Mechanical energy balance in turbulent flow
• D. Mechanical energy balance in potential flow

Explanation: Bernoulli's equation is a mechanical-energy balance for steady, incompressible, frictionless flow, commonly represented as potential flow.

• A. Shear stress over the cross-section is proportional to the distance from the surface of the pipe
• B. Average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)
• C. volume of circumscribing cylinder
• D. Velocity profile varies hyperbolically and the shear stress remains constant over the crosssection
• E. Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the

Explanation: For laminar flow in a circular pipe, the velocity profile is parabolic, so its solid of revolution is a paraboloid whose volume is half…

• A. Increase the structural strength of the tank
• B. Reduce swirling and vortex formation
• C. Aid in rotational flow
• D. None of these

Explanation: Baffles interrupt tangential fluid motion in a mixing tank, preventing excessive swirling and vortex formation.

• A. Venturimeter
• B. Orificemeter
• C. Rotameter
• D. Weir

Explanation: A weir measures open-channel flow by relating the upstream liquid head to the discharge over the crest.

• A. 0.01
• B. 0.1
• C. 1
• D. 10

Explanation: Water has a dynamic viscosity of approximately 0.001 Pa.s at room temperature; multiplying by 100 gives 0.1 Pa.s.

• A. Gravity forces
• B. Turbulent forces
• C. Pressure forces
• D. Viscous forces

Explanation: The Navier-Stokes equation explicitly includes pressure, viscous, and body forces such as gravity.

• A. 2
• B. 2.828
• C. 5.657
• D. 4

Explanation: For a triangular (V-notch) weir, discharge varies as H^(5/2). Doubling the head therefore multiplies discharge by 2^(5/2) = 5.657.