All Free Chemical Engineering MCQs with Answers

• A. Butyl alcohol
• B. Propyl alcohol
• C. Methyl alcohol
• D. Ethanol

Explanation: In ordinary industrial and commercial usage, the term alcohol without a qualifier generally refers to ethanol.

• A. All A , B, & C.
• B. Charcoal
• C. Potassium nitrate
• D. Sulphur

Explanation: Traditional gunpowder is a mechanical mixture of potassium nitrate as the oxidizer, charcoal as the fuel, and sulphur as a combustible…

• A. Phosphate rock with phosphoric acid
• B. Phosphate rock with sulphuric acid
• C. Phosphate rock with nitric acid
• D. Ammonium phosphate with phosphoric acid

Explanation: Triple superphosphate is made by treating phosphate rock with phosphoric acid, producing a concentrated phosphate fertilizer rich in…

• A. 15
• B. 35
• C. 55
• D. 70

Explanation: Indian pyrites are relatively low-grade compared with pure pyrite, with an average sulphur content of about 35 percent.

• A. Bakelite
• B. Celluloid
• C. Teflon
• D. Dacron

Explanation: Teflon is the trade name for polytetrafluoroethylene, a chemically resistant fluoropolymer with a very low coefficient of friction.

• A. None of these
• B. Inhibits its corrosive effects
• C. Does not allow redeposition of dirt on the cleaned surface
• D. Facilitates its use even in hard water (by sequestering the water-hardening Ca & Mg ions)

Explanation: Sodium tripolyphosphate acts as a builder by binding calcium and magnesium ions, reducing water hardness and allowing detergent to work…

• A. Distillation
• B. None of these
• C. Dehydrogenation
• D. Dehydration

Explanation: Ethyl alcohol is first produced from molasses by fermentation, whereas distillation only separates and concentrates the alcohol afterward.

• A. Benzoic acid
• B. Isoprene
• C. Phenol and acetone
• D. Styrene

Explanation: Cumene is oxidised to cumene hydroperoxide, which decomposes to give phenol and acetone.

• A. Rocket propellant
• B. Explosive
• C. Plasticiser
• D. Fat

Explanation: Margarine is an edible fat made by hydrogenating or otherwise modifying vegetable oils, often with blending and emulsification.

• A. 70
• B. 640
• C. 1875
• D. 2500

Explanation: Seawater contains bromide equivalent to roughly 60 to 70 ppm bromine, so 70 ppm is the closest option.

• A. Blue vitriol
• B. Gypsum
• C. Calcium silicate
• D. Calcium sulphate

Explanation: Gypsum, CaSO4·2H2O, loses part of its water of crystallisation on heating near 120°C and forms plaster of Paris, CaSO4·½H2O.

• A. Rosin
• B. Benzyl acetate
• C. Borax
• D. Sodium carbonate

Explanation: Borax acts as a binding and conditioning additive in soap, helping improve its texture and consistency.

• A. (NH4)2SO4
• B. CaCl(OCl)
• C. CaSO4.H2O
• D. Na2SO4.10H2O

Explanation: Glauber's salt is hydrated sodium sulphate, Na2SO4·10H2O. The other formulas represent bleaching powder, gypsum-related calcium sulphate…

• A. Gypsum
• B. Silicates
• C. Sodium silicate
• D. Carbonates

Explanation: Portland cement is composed mainly of calcium silicates, with calcium aluminates and ferrites as important clinker compounds.

• A. Facilitate easy regeneration of zeolite
• B. Increase the softening capacity of zeolite
• C. Permit the use of alum as a coagulant
• D. All A , B. and C.

Explanation: Soda ash supplies carbonate alkalinity, which neutralizes the acidity produced when alum hydrolyses and allows alum to form effective…

• A. Liquid chlorines
• B. Chloramines
• C. Sodium bisulphite
• D. Brine

Explanation: Zeolite exchanges its sodium ions for calcium and magnesium during softening.

• A. Slaked lime
• B. Quicklime
• C. Milk of lime
• D. None of these

Explanation: Calcium oxide reacts exothermically with water to form calcium hydroxide, Ca(OH)₂, commonly called slaked lime.

• A. Xanthates
• B. Calcium & aluminium stearate
• C. Stearic acid
• D. Formic acid

Explanation: Calcium and aluminium stearates form water-repellent coatings within cement pores, reducing the cement's hydrophilic character.

• A. As a starting material for 'hypo'
• B. As rocket fuel
• C. In photographic industry
• D. In printing industry

Explanation: Hydrazine is a powerful reducing fuel with a high energy release and is used in rocket and spacecraft propulsion systems.

• A. 500°C
• B. 750°C
• C. 1000°C
• D. 1500°C

Explanation: Limestone calcination requires roughly 900 to 1100°C, with about 1000°C being the standard value used for the calcination zone.