Free Chemical Process Principles MCQs with Answers

• A. Presence of large quantity of hydrogen in the fuel
• B. Low calorific value of the fuel
• C. High sulphur content in the fuel
• D. Lack of thorough mixing of fuel with air

Explanation: Even with excess air, incomplete contact between the fuel and air can leave carbon only partly oxidised, producing substantial carbon…

• A. Ammonium sulphate
• B. Ammonium nitrate
• C. Ammonium phosphate
• D. None of these

Explanation: Ammonia recovered from coke-oven gas is reacted with sulphuric acid in the by-products plant to form ammonium sulphate, a valuable…

• A. C2H6
• B. CH4 (upto 90%)
• C. C3H8
• D. H2

Explanation: Methane is the dominant component of natural gas, commonly reaching about 90% or more depending on the field and processing.

• A. Removing ash from the coal based on difference in specific gravity of coal and ash
• B. Washing lump coal (> 80 mm size)
• C. Washing fine coal dust (< 0.5 mm size)
• D. All A., B. and C.

Explanation: Froth flotation is particularly suitable for fine coal particles, where hydrophobic coal attaches to air bubbles and rises as froth.

• A. Recarbonising steel
• B. All A., B. and C.
• C. Blending with highly coking coal to check its swelling which helps in saving coke even walls
• D. from damage and to produce high strength coke
• E. Making carbon electrodes

Explanation: Anthracite is a high-carbon, low-volatile, non-caking coal, so it can serve as a steel recarburiser, an electrode-carbon source and a…

• A. 5
• B. 25
• C. 55
• D. 75

Explanation: In the usual coke-oven-gas recovery sequence, the primary cooler removes roughly one-quarter of the total tar; much of the remaining tar…

• A. Ash content in the fuel
• B. Flue gases
• C. Incomplete combustion
• D. Unburnt carbon in flue gases

Explanation: Flue-gas loss is usually the largest boiler loss because a large mass of hot exhaust gases carries sensible heat out of the furnace.

• A. Insecticides (e.g. moth balls)
• B. Unsaturated polyesters
• C. All A., B. and C.
• D. Drug intermediates e.g. β-naphthol

Explanation: Naphthalene is used in mothballs and insecticides, converted to phthalic anhydride for unsaturated polyesters, and used to make drug…

• A. 2.4
• B. 1.75
• C. 0.87
• D. 11.4

Explanation: Combustion requires 0.5 Nm³ of O₂ per Nm³ of CO: 2CO + O₂ → 2CO₂. Since dry air contains about 21% oxygen, the theoretical air requirement…

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

Explanation: In an Orsat analysis, alkaline pyrogallol selectively absorbs oxygen, while potassium hydroxide absorbs carbon dioxide and cuprous…

• A. Low temperature carbonisation
• B. Medium temperature carbonisation
• C. High temperature carbonisation
• D. Heating the coal in an oven in presence of air

Explanation: Blast-furnace coke is produced by high-temperature carbonisation of coal, usually around 900–1200°C in the absence of air.

• A. Increase
• B. Not change
• C. Increase or decrease depending on the fuel type
• D. Decrease

Explanation: Increasing the air/fuel ratio adds excess nitrogen and oxygen that must be heated, so more heat is carried by the combustion gases and the…

• A. Metallurgical coke
• B. No by-products
• C. Very low calorific value coke oven gas
• D. Soft coke

Explanation: Low-temperature carbonisation produces a relatively soft, more volatile coke along with larger amounts of tar and gas.

• A. 2.5
• B. 0.5
• C. 10
• D. 20

Explanation: In narrow coke ovens operated for high-temperature carbonisation, the heat penetrates the coal charge at approximately 2.5 cm per hour.

• A. Ash fusion temperature
• B. Calorific value
• C. Ignition temperature
• D. Caking index

Explanation: A higher volatile-matter content generally makes coal ignite more readily, so its ignition temperature is lower.

• A. Transport the coal to the burner
• B. Dry the coal
• C. Reduce primary air requirement
• D. Ensure efficient burning of coal around the burner

Explanation: Primary air carries and partly dries the pulverised coal, whereas secondary air supplies additional oxygen around the burner for thorough…

• A. Permits the use of high ash content coal
• B. Permits the use of low fusion point ash coal
• C. Accelerates the burning rate and economises on fuel combustion
• D. All A., B. and C.

Explanation: Pulverisation greatly increases the coal surface area, accelerating combustion and allowing more complete burning with efficient fuel…

• A. Junker's
• B. Bomb
• C. Boy's
• D. None of these

Explanation: A bomb calorimeter measures the heat released by burning solid and liquid fuels in a sealed vessel at constant volume.

• A. Lignite
• B. Sub-bituminous
• C. Semi-anthracite
• D. Bituminous

Explanation: Coal rank increases from lignite through sub-bituminous and bituminous to anthracite; semi-anthracite lies between anthracite and…

• A. Volatile matter content increases
• B. Carbon content decreases
• C. Moisture content increases
• D. Ash content increases

Explanation: As coal rank decreases from anthracite to lignite, volatile matter increases and makes ignition easier, so the ignition temperature falls.