Free Chemical Process Principles MCQs with Answers

• A. Cristobalite
• B. Quartz
• C. Tridymite
• D. None of these

Explanation: Quartz is the stable crystalline form of silica at room temperature, specifically the low-temperature alpha-quartz form.

• A. 1800
• B. 2200
• C. 2400
• D. 2700

Explanation: Silicon carbide refractories have an extremely high refractoriness, commonly quoted at about 2700°C.

• A. Side wall of soaking pits
• B. Walls of coke oven
• C. Regenerators of coke oven
• D. Hearth of blast furnace

Explanation: Carbon refractories are used chiefly in the hearth of a blast furnace because carbon resists attack by molten iron and slag and tolerates…

• A. None of these
• B. Thermal conductivity
• C. Resistance to thermal shock
• D. Refractoriness (< 1700°C)

Explanation: Silicon carbide has high refractoriness, high thermal conductivity, and excellent thermal-shock resistance, so none of the listed…

• A. Producing monolithic linings
• B. Patch work
• C. All A., B. and C.
• D. Minimising the number of joints in the structure

Explanation: Castables are refractory concretes that form monolithic linings, are convenient for patching damaged areas, and reduce the number of…

• A. Zircon
• B. Fireclay
• C. Alumina
• D. Graphite

Explanation: Graphite conducts electricity through its delocalised carbon electrons and therefore has far lower electrical resistivity than fireclay…

• A. 14-20
• B. 5-7
• C. 7-12
• D. 2-3

Explanation: A refractory mix prepared for hand moulding may require relatively high moisture for plasticity, with the maximum commonly taken as about…

• A. Thoria
• B. Fireclay
• C. High alumina
• D. Silicon carbide

Explanation: High-alumina bricks are used in the burning zone of cement rotary kilns because they withstand high temperature, abrasion, and chemical…

• A. 10
• B. 25
• C. 50
• D. 80

Explanation: Air-dried wood commonly contains about 50% carbon by weight, with the remainder mainly oxygen, hydrogen, moisture and mineral matter.

• A. Blast furnace gas
• B. Coke oven gas
• C. Sewage gas
• D. Natural gas

Explanation: Blast furnace gas is heavily diluted with nitrogen and carbon dioxide, so its heating value is only about 800 to 1,000 kcal/Nm³.

• A. Maximum to minimum heat input ratio
• B. Both A. & B.
• C. Maximum to minimum permissible gas flow rate
• D. Minimum to maximum heat input ratio

Explanation: Turndown is the range over which a burner operates satisfactorily, expressed as maximum divided by minimum firing rate.

• A. Gobar gas
• B. Refinery gas
• C. Converter gas
• D. Blast furnace gas

Explanation: Blast furnace gas has the lowest heating value because most of it is nitrogen, with substantial carbon dioxide and only a small amount of…

• A. More than
• B. Less than
• C. Equal to
• D. Either more or less; depends on the type of fuel

Explanation: Fuel ignites more readily in pure oxygen, so its ignition temperature is lower than in air.

• A. MgSO4 & BaCl2
• B. MgO & Na2CO3
• C. BaSO4 & NaCl
• D. MgCO3 & NaCl

Explanation: Eschka mixture consists of magnesium oxide and sodium carbonate, commonly mixed in a 2:1 ratio.

• A. Decreases the hardness of coke
• B. Decreases the abrasion resistance of coke
• C. Causes brittleness in steel
• D. None of these

Explanation: Coal ash is undesirable in metallurgical coke because it increases slag formation and lowers the effective fixed-carbon content.

• A. 500
• B. 750
• C. 950
• D. 1100

Explanation: In proximate analysis, coal is heated in air at approximately 750°C until its combustible matter is removed and only mineral residue…

• A. If its ash content is zero
• B. If its hydrogen/hydrogen compound content is zero
• C. If its carbon content is very low
• D. Under no circumstances

Explanation: Gross calorific value includes the heat recovered when water formed from hydrogen condenses, whereas net calorific value excludes this…

• A. 71%
• B. None of these
• C. In between 37 & 71%

Explanation: An explosion-limit range gives the concentrations between the lower and upper flammability limits at which combustion can propagate.

• A. 30
• B. 50
• C. 75
• D. 95

Explanation: Carbonisation of metallurgical coal commonly gives roughly 70–75% coke by mass, with the remainder becoming gas, tar, liquor and other…

• A. Sand (40%)
• B. Carbon tetrachloride
• C. Mineral oil of high viscosity & specific gravity (1.6)
• D. None of these

Explanation: Coal washery liquids commonly use water mixed with sand to form a dense medium for separating coal from heavier mineral matter.