All Free Chemical Engineering MCQs with Answers

• A. Atmospheric
• B. 10 atm
• C. Vacuum
• D. 3 atm

Explanation: A crude topping column performs the initial atmospheric distillation of crude oil, separating gases, naphtha, kerosene and gas oils near…

• A. Aluminium chloride
• B. Phosphoric acid on kieselguhr
• C. Nickel
• D. Vanadium pentoxide

Explanation: Catalytic polymerisation of light olefins traditionally uses phosphoric acid supported on kieselguhr.

• A. Calcium
• B. Potassium
• C. Magnesium
• D. Sodium

Explanation: Magnesium chloride hydrolyses during crude-oil distillation to form hydrochloric acid, making it a major source of corrosive HCl.

• A. Diesel
• B. Gasoline
• C. Naphtha
• D. Atmospheric residue

Explanation: Atmospheric residue is the heaviest petroleum fraction and retains most of the sulphur-containing compounds after distillation.

• A. High smoke point
• B. Low smoke point
• C. High aromatics content
• D. Low paraffins content

Explanation: A high smoke point indicates that kerosene burns with little tendency to form soot or smoke.

• A. pH value
• B. All A., B. and C.
• C. Temperature
• D. Water percentage

Explanation: The conductivity of a crude oil-water mixture changes with its water fraction, ionic character or pH, and temperature.

• A. 100
• B. 0
• C. 70
• D. ∞

Explanation: The octane-number scale uses n-heptane as the zero reference fuel and isooctane as the 100 reference fuel.

• A. PCM
• B. Tar
• C. Low viscosity furnace oil
• D. Light diesel oil

Explanation: Light diesel oil has sufficiently low viscosity to flow and atomise without preheating.

• A. 1
• B. 20
• C. 100
• D. 500

Explanation: Char value measures carbonaceous deposit left on the wick during standard burning, so a lower value indicates cleaner kerosene.

• A. Liquid petroleum gas
• B. Liquefied petroleum gas
• C. Liquid petrol gas
• D. Liquefied petrol gas

Explanation: LPG means liquefied petroleum gas: petroleum-derived hydrocarbons, mainly propane and butane, stored as a liquid under pressure.

• A. 0.03
• B. 3
• C. 35
• D. 70

Explanation: Electrostatic desalting removes most brine and reduces residual salt in crude oil to roughly 3 pounds per thousand barrels.

• A. Unsaturated hydrocarbon content
• B. Quantity of butane
• C. Quantity of propane
• D. Calorific value

Explanation: Wet natural gas contains more heavier hydrocarbons such as propane, butane and higher components than dry gas.

• A. Furnace oil
• B. Kerosene
• C. Petrol
• D. Diesel

Explanation: API gravity decreases as petroleum becomes denser and heavier. Furnace oil is the heaviest option listed, so it has the lowest API gravity.

• A. Thermal cracking
• B. Coking
• C. Gum formation
• D. Discoloration

Explanation: Vacuum lowers boiling temperatures so heavy fractions can be distilled without severe thermal damage.

• A. Kjeldahl
• B. Dumas
• C. Junkers calorimeter
• D. Bomb calorimeter

Explanation: In the bomb method, the crude oil is completely burned in oxygen and the sulfur oxides formed are measured, allowing sulfur content to be…

• A. Freezing point
• B. Viscosity
• C. Calorific value
• D. Flash point

Explanation: Jet fuel must remain fluid at the very low temperatures encountered at high altitude, making a low freezing point essential.

• A. Sulphur content
• B. Aniline point
• C. Viscosity
• D. Flash point

Explanation: Sulphur content, viscosity and flash point directly affect fuel-oil handling, combustion and safety.

• A. It is highly aromatic in nature
• B. It has a very low diesel index
• C. It is highly paraffinic in nature
• D. Its ignition quality is very poor

Explanation: Aniline point increases with paraffinic character and decreases with aromatic content because aromatics dissolve more readily in aniline.

• A. High boiling naphthenes
• B. Methane & ethane
• C. High boiling olefins
• D. Propane & butane

Explanation: Commercial LPG consists mainly of the light hydrocarbons propane and butane, supplied either separately or as a blend.

• A. Aromatics
• B. i-paraffins
• C. Naphthene
• D. Olefins

Explanation: Aromatics generally have the poorest ignition quality among the listed hydrocarbon classes and therefore the lowest cetane numbers.