Free Chemical Process Principles MCQs with Answers

• A. Size
• B. Specific gravity
• C. Terminal velocities in the same fluid & in the same field of force
• D. None of these

Explanation: Equal-settling particles are defined by having the same terminal settling velocity in the same fluid and under the same force field.

• A. Linear inch
• B. Square inch
• C. Square foot
• D. Linear foot

Explanation: Mesh number specifies the number of openings along one linear inch of screen.

• A. Belt conveyor
• B. Flight conveyor
• C. Apron conveyor
• D. Chain conveyor

Explanation: Flight conveyors use flights moving through a casing or trough, so abrasive solids cause substantial wear on the flights and casing and…

• A. 3.6 W.V.ρ
• B. 3.6 W.D.V
• C. 3.6 W.D.V.ρ
• D. 3.6 D.V.ρ

Explanation: Volumetric throughput is WD V, and multiplying by bulk density gives kg/s; conversion from kg/s to tonnes per hour supplies the factor…

• A. Iron ores
• B. Quartzite
• C. Sulphide ores
• D. None of these

Explanation: Froth flotation is especially effective for sulphide ores because collectors make the desired sulphide mineral particles hydrophobic…

• A. mixer-extruder
• B. Pug mill
• C. Muller mixer
• D. Banbury internal mixer

Explanation: The Banbury internal mixer provides intense shear and distributive mixing in a closed chamber, making it the standard mixer for rubber…

• A. cos α = (dr + dp)/(dr + df)
• B. cos α = (dr + df)/(dr + dp)
• C. tan α = (dr + dp)/(dr + df)
• D. sin α = (dr + dp)/(dr + df)

Explanation: For a roll crusher, the geometric nip relation is cos α = (dr + dp)/(dr + df), where the feed particle diameter and roll gap determine the…

• A. 10
• B. 25
• C. 50
• D. 75

Explanation: A ball charge of about 50% of the mill volume gives the greatest practical capacity because it provides many grinding contacts without…

• A. Tube
• B. Compartment
• C. Pebble
• D. Ring-roll

Explanation: Ring-roll mills are commonly used for fine grinding of soft minerals such as talc.

• A. Compression
• B. Dispersion
• C. Pulverisation
• D. Comminution

Explanation: Comminution, dispersion and pulverisation describe reducing or dispersing solids into fine particles.

• A. cm2
• B. inch
• C. cm
• D. inch2

Explanation: Mesh size is defined by the number of openings along one linear inch of the screen, not by openings per square inch.

• A. Run at very high rpm
• B. Suitable for highly abrasive materials
• C. Suitable for sticky materials
• D. All A., B. and C.

Explanation: Screw conveyors operate at relatively low speed and can handle sticky or cohesive materials effectively.

• A. Jigging
• B. Elutriation
• C. Froth floatation
• D. Tabling

Explanation: Gravity concentration on shaking tables is widely used to recover the high-density gold fraction from crushed ore, especially fine…

• A. Jaw crusher
• B. Fluid energy mill
• C. Ball mill
• D. Rod mill

Explanation: A fluid energy mill produces extremely fine particles by high-velocity fluid jets and particle-to-particle impact, requiring considerable…

• A. Depressor
• B. Collector
• C. Frother
• D. Conditioner

Explanation: Pine oil and cresylic acid reduce froth surface tension and help form stable bubbles, so they act as frothers.

• A. μ > tan α
• B. μ ≤ tan α
• C. μ > tan 2α
• D. μ ≥ tan α

Explanation: For particles to be nipped and drawn into the rolls, the friction coefficient must satisfy μ ≥ tan α, where α is half the angle of nip.

• A. Corona discharge
• B. Electric spark
• C. Alternating current
• D. None of these

Explanation: A Cottrell precipitator charges dust particles by corona discharge and then collects them on oppositely charged electrodes.

• A. Fine (e.g. - 200 mesh size coal)
• B. Sticky (e.g. clay paste)
• C. Small lumpy (e.g. grains and sand)
• D. Free flowing

Explanation: Bucket elevators require material that can flow and discharge readily from the buckets.

• A. Employs smaller balls
• B. Gives finer size reduction but consumes more power
• C. All A., B. and C.
• D. Has larger length/diameter ratio (>2 as compared to 1 for ball mill)

Explanation: A tube mill has a larger length-to-diameter ratio, uses smaller grinding balls, and generally produces finer material at higher power…

• A. Wet grinding achieves a finer product size than dry grinding
• B. Its capacity decreases with increasing fineness of the products
• C. Grinding cost and power requirement increases with increasing fineness of the products
• D. All A., B. and C

Explanation: Wet grinding can produce a finer product, while increasing fineness lowers mill capacity and raises both power use and grinding cost.