Free Chemical Process Principles MCQs with Answers

• A. Ensure its complete combustion
• B. Facilitate easy ash removal
• C. Enhance its calorific value
• D. Provide trouble free operation

Explanation: Pulverising coal increases its surface area, allowing better contact with air and making combustion more nearly complete.

• A. Give less yield of tar and gas on carbonisation
• B. Burn with a small non-smoky flame
• C. None of these
• D. Have a very high calorific value

Explanation: High-volatile coal produces greater quantities of tar and gas during carbonisation and generally burns with a long, smoky flame.

• A. Auto catalytic
• B. None of these
• C. Endothermic
• D. Exothermic

Explanation: Combustion releases the chemical energy of the fuel as heat, so its enthalpy change is negative and the reaction is exothermic.

• A. Same
• B. Less
• C. More
• D. Data insufficient; can't be predicted

Explanation: The difference between gross and net calorific value is the heat recovered by condensing water vapour formed from hydrogen in the fuel.

• A. Sulphur content
• B. Both A. & B.
• C. Calorific value
• D. Neither A. nor B.

Explanation: A bomb calorimeter directly measures the heat released on complete combustion and therefore gives the coal's gross calorific value.

• A. N2
• B. CH4
• C. H2
• D. CO2

Explanation: Hydrogen is usually the largest component of coke-oven gas, formed during the destructive distillation of coal.

• A. Lower than
• B. Higher than
• C. Same as
• D. Not related to

Explanation: Air gives a lower adiabatic flame temperature than pure oxygen because its nitrogen acts as inert ballast, absorbing heat and diluting the…

• A. Excessive power requirement of air blower
• B. Enhanced sensible heat loss in the flue gas
• C. Intermittent and uncontrolled combustion of the fuel
• D. High exit flue gas temperature from the furnace

Explanation: Excess air increases the amount of nitrogen and unused oxygen carried through the furnace, so more hot flue gas must be heated and…

• A. Rotary cup
• B. Outside mixing/diffusion flame/nozzle mix type
• C. Inside mixing/premix type
• D. Submerged combustion

Explanation: A Bunsen burner mixes gas with primary air inside the burner tube before ignition, making it an inside-mixing or premix burner.

• A. 100
• B. 500
• C. 1000
• D. 1500

Explanation: Pulverised coal contains substantial void space between particles, so its bulk density is much lower than the true density of coal.

• A. Coke breeze containing 25% ash and 2% volatile matter
• B. Anthracite containing 10% volatile matter and 8% ash
• C. Bituminous coal containing 20% ash and 25% volatile matter
• D. Semi-bituminous coal containing 25% ash and 20% volatile matter

Explanation: Secondary air mainly burns volatile combustible gases released from the fuel.

• A. 850
• B. 1800
• C. 4200
• D. 6500

Explanation: Blast-furnace gas contains much nitrogen and carbon dioxide, which dilute its combustible carbon monoxide and give it a low heating value.

• A. Is present upto 1-2%
• B. Comes from protein in parent vegetable matter
• C. Is recovered as ammonia during its carbonisation
• D. All A., B. and C.

Explanation: Coal nitrogen is commonly about 1 to 2% and originates largely from proteins in the parent plant material.

• A. CH4
• B. CO2
• C. H2
• D. CO

Explanation: Methane is usually the major combustible constituent of natural gas and has a high heating value.

• A. Potassium hydroxide
• B. Cuprous chloride
• C. Alkaline pyrogallol solution
• D. None of these

Explanation: In Orsat analysis, cuprous chloride selectively absorbs carbon monoxide.

• A. Proximate analysis
• B. Calorific value
• C. Caking index
• D. Ultimate analysis

Explanation: Seyler’s classification uses the coal’s elemental composition, especially carbon and hydrogen percentages, which are obtained from…

• A. C + H2O ↔ CO + H2
• B. C + 2H2O ↔ CO2 + 2H2
• C. None of these
• D. CO + H2O ↔ CO2 + H2

Explanation: The water-gas shift reaction converts carbon monoxide and steam into carbon dioxide and hydrogen: CO + H₂O ⇌ CO₂ + H₂.

• A. CH4
• B. H2
• C. CO2
• D. N2

Explanation: Anaerobic bacteria convert organic matter into biogas, whose principal combustible component is methane.

• A. Abradability
• B. Reactivity
• C. Agglutinating (binding) properties
• D. Porosity

Explanation: The caking index indicates how strongly coal particles soften and bind together when heated, forming a coherent coke.

• A. Polyurethane
• B. Bakelite
• C. Teflon
• D. SBR

Explanation: Buna-S is the conventional name for styrene-butadiene rubber, abbreviated SBR.