All Free Chemical Engineering MCQs with Answers

• A. Mineral salts
• B. Carbohydrates
• C. Proteins
• D. Fats

Explanation: Proteins contain nitrogen because their amino acids include amino groups, unlike carbohydrates and fats, which normally contain only…

• A. Pyrex
• B. None of these
• C. Crookes
• D. Flint

Explanation: Flint glass contains lead oxide, which gives it a high refractive index and strong dispersion, making it useful in optical instruments.

• A. Sodium hexametaphosphate
• B. Sodium phosphate
• C. Calcium phosphate
• D. Tricresyl phosphate

Explanation: Calgon is sodium hexametaphosphate, which complexes calcium and magnesium ions and helps prevent scale formation.

• A. After
• B. Before
• C. During
• D. To avoid

Explanation: Coagulants destabilise and clump fine suspended particles into flocs, which are then removed by filtration.

• A. Solvay
• B. None of these
• C. Haber's
• D. Ostwald's

Explanation: The Ostwald process oxidises ammonia catalytically to nitric oxide, which is further oxidised and absorbed to form nitric acid.

• A. All A , B. & C .
• B. Hissing sound
• C. Slaked lime
• D. Exothermic heat

Explanation: Quicklime reacts with water to form slaked lime, Ca(OH)₂, and the hydration releases substantial heat, often producing a hissing sound.

• A. Fire extinguishing compounds
• B. All A , B. and C.
• C. Dyes and antiknock compounds
• D. Fire proofing agents

Explanation: Bromine compounds have been used in fire extinguishing and fireproofing materials, and bromine is also important in dyes and antiknock…

• A. High electrical insulation properties
• B. Low co-efficient of thermal expansion
• C. Sharp melting points
• D. Compressive strength much greater than their tensile strengths

Explanation: Glass is amorphous, so it softens over a temperature range rather than having a sharp melting point.

• A. Colourless rosin is used in the manufacture of laundry soaps
• B. Organic pigments are used as colouring materials in the soap manufacture
• C. Both laundry as well as toilet soaps are manufactured by hot process
• D. Transparent soaps are made by cold process

Explanation: Transparent soaps are generally produced by the hot process, followed by treatment with alcohol, glycerol or sugar to give transparency.

• A. Sintering
• B. Annealing
• C. Shaping or forming
• D. Melting

Explanation: Glass manufacture involves batch melting, shaping or forming, and annealing to remove internal stresses.

• A. Activated clay
• B. Chlorine or chlorine dioxide
• C. Bromine
• D. Magnesium sulphite

Explanation: Pulp bleaching commonly uses chlorine or chlorine dioxide to oxidise and remove residual lignin and colour-producing substances.

• A. Roasting
• B. Smelting
• C. Electromagnetic separation
• D. Froth floatation

Explanation: Sulphide ores are commonly concentrated by froth flotation because their sulphide particles preferentially attach to air bubbles and rise…

• A. Requires lesser investment for similar capacity
• B. Requires less specific power consumption for the production of chlorine
• C. Produces 70% NaOH solution
• D. All A , B. and C

Explanation: A diaphragm cell produces dilute caustic soda, not 70% solution, and generally consumes more power than a mercury cell.

• A. Aeration of water is effective in CO2 removal
• B. The zeolite water softening process reduces the hardness of water by not more than 50%
• C. Sodium sulphate or sodium carbonate do not cause hardness in water
• D. Water with pH value less than 7, is acidic

Explanation: Zeolite softening removes hardness effectively by exchanging calcium and magnesium ions for sodium ions, not merely by 50% or less.

• A. 0.14
• B. 0.34
• C. 0.94
• D. 1.4

Explanation: Argon makes up about 0.934% by volume of dry atmospheric air, after nitrogen and oxygen in abundance.

• A. Reduces
• B. Oxidises
• C. Adsorbs
• D. Converts

Explanation: Wood charcoal has a highly porous surface that adsorbs colouring substances from the sugar solution.

• A. Paint
• B. Oil hydrogenation
• C. Soap
• D. Sugar

Explanation: Massecuite is the mixture of sugar crystals and mother liquor formed during sugar boiling and crystallisation.

• A. Slow sand filters can remove colour completely
• B. Normally, the turbidity is removed by adding a coagulant prior to sedimentation
• C. Application of activated carbon reduces the temporary hardness of water
• D. Activated carbon can be used for taste & odour control without subsequent filtration

Explanation: Coagulation destabilises suspended particles, allowing them to form flocs that are removed by subsequent sedimentation.

• A. CaO
• B. MnO2
• C. ZnO
• D. FeS

Explanation: ZnO modifies the glass network and lowers its coefficient of thermal expansion, improving resistance to thermal shock.

• A. SO3
• B. SO2
• C. H2SO3
• D. H2SO4

Explanation: Oleum is sulfuric acid containing dissolved excess SO3, and its strength is commonly expressed as equivalent H2SO4 percentage.