Chemical Engineering Basics — Part 1 MCQs with Explanations

The volume of blast furnace slag is about 3 times the volume of hot metal (pig iron) of the same weight. In the blast furnace process, iron ore (mainly iron oxide) is reduced to produce pig iron, and the impurities in the ore (like silica and alumina) combine with flux (like limestone) to form slag. The slag is less dense than pig iron, which leads to it occupying more volume for the same weight. Typically, for every ton of pig iron produced, approximately 3 tons of blast furnace slag are generated, meaning the volume of slag is about three times that of the hot metal. Option A: 1.5 This option is incorrect . The volume of slag is far more than 1.5 times the volume of hot metal. The ratio is much higher. Option C: 5 This option is incorrect . The volume of slag is not five times that of the hot metal. A ratio of 3:1 is more common and realistic for most blast furnace operations. Option D: 7 This option is incorrect . Although the volume of slag can vary based on the specific process and furnace conditions, the typical ratio is about 3:1, not 7:1. Therefore, the correct answer is Option B: 3 , which is the typical volume ratio of blast furnace slag to pig iron.

Radiation: The heat transfer by radiation is independent of surface texture (like cavities or pock-marks) and relies on the emissivity and temperature of the surface. Hence, the heat transfer by radiation does not increase due to the presence of cavities. Convection: Cavities on a heat transfer surface can enhance convection by disturbing the boundary layer, promoting turbulence and fluid mixing. This increases the rate of convective heat transfer. Nucleate Boiling: Cavities act as nucleation sites, facilitating bubble formation and improving heat transfer during boiling. Conduction: Surface irregularities could affect conduction slightly but are less significant in comparison to the other modes of heat transfer. Thus, Option C: Radiation is the correct answer because it remains unaffected, while other modes of heat transfer may increase with a pock-marked surface.

The correct answer is A: Decreases but dew point remains constant. Let's break down why: Sensible cooling means you're only changing the temperature of the air, not the amount of moisture in it. Think of it like this: you're cooling the air, but you're not taking any water out. Wet bulb temperature is the temperature a parcel of air would have if cooled to saturation (100% relative humidity) by the evaporation of water into it, with the latent heat being supplied by the parcel. When you cool the air *without* changing the amount of water vapor present, the wet-bulb temperature will also decrease . The dew point is the temperature to which air must be cooled to become saturated with water vapor. Since the amount of moisture in the air is constant during sensible cooling, the dew point remains constant . Therefore, wet bulb temperature decreases and dew point remains constant .

Brinell Hardness Number (BHN) is a measure of the hardness of materials, with higher values indicating harder materials. Talc is a soft mineral, often used in cosmetics and as a lubricant. The BHN of talc is very low, typically falling within the range of 1-5 , indicating its softness compared to other materials.

Cohesive Forces: Attractive forces between molecules of the same type are called cohesive forces. Adhesive Forces: Attractive forces between molecules of different types are called adhesive forces. Surface Tension: Cohesive forces between molecules cause the surface of a liquid to contract to the smallest possible surface area. This general effect is called surface tension. Source : lumenlearning.com

Rubber is the most elastic material among the options provided. A highly elastic material deforms the least on loading and retains its original form on removal of the load. Rubber exhibits high elasticity due to its molecular structure, which allows it to undergo significant deformation under stress and return to its original shape once the stress is removed. Steel is a strong material but not as elastic as rubber. It exhibits more plastic deformation under stress, meaning it retains some of the deformed shape even after the load is removed. Glass is brittle and exhibits minimal elasticity. It fractures easily under stress and does not return to its original shape once deformed. Brass is a metal alloy that is ductile but not as elastic as rubber. It deforms plastically under stress and does not regain its original shape completely upon load removal. Therefore, Option C: Rubber is the most elastic material among the given options.

In chemical engineering, the approximate height of a blast furnace can be estimated based on its useful volume. A commonly used estimation is that the height of a blast furnace is approximately 10 to 30 times its useful volume. Given that the useful volume of the blast furnace is 2000 m 3 , we can estimate the height as follows: Height ≈ 10 to 30 * Volume Taking the average value (20 times the volume) for estimation: Height ≈ 20 * 2000 m 3 Height ≈ 40000 m 3 Therefore, the approximate height of the blast furnace is 55 metres , which is closest to Option C.

Malleable iron is the correct answer to “Which of the following will resist maxi-mum shock & vibration without cracking”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Pulverised fuel is the correct answer to “The most commonly used combustion system manufactured in India for the thermal power plant boilers is the __________ combustion system.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Elastic properties is the correct answer to “Isotropic materials have the same __________ in all directions.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Flakes is the correct answer to “Carbon is present in the form of __________ in grey cast iron.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Farenhite is the correct answer to “First empirical temperature scale conceived is the __________ temperature scale.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

None of these is the correct answer to “Pick out the wrong statement.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Semi-conductor is the correct answer to “Materials having resistivity ranging from 1 to 100 ohm. cm is termed as”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Corrosion resistant is the correct answer to “Alloys having more than 80% copper are generally more”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Liquid oxygen is the correct answer to “Which of the following is not used as a fuel in rocket propellaht”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Universal testing machine is the correct answer to “Toughness of a material is measured by the”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Endurance limit is the correct answer to “Fatigue resistance of a material is measured by the”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

In the elastic range is the correct answer to “The stress at which a metal fails by fatigue lies”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Its efficiency will not be affected is the correct answer to “Pick out the wrong statement. If the net positive suction head (NPSH) requirement of a pump is not satisfied, then”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Index is the correct answer to “The ratio of coil diameter to wire diameter of a spring is called the spring”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Uses molten sodium as moderator is the correct answer to “Pick out the wrong statement about a fast breeder reactor.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Reduce & melt the iron ore is the correct answer to “Coke is added in the blast furnace to”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Silicon is the correct answer to “Castability of aluminium is increased by the addition of __________ in it.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Pitot tube is the correct answer to “Speed of a submarine in deep sea & that of an aeroplane is measured by a/an”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Moisture is the correct answer to “Chlorine acts as a bleaching agent only in the presence of”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Rate of return criterion is the correct answer to “The best criterion for analysing an economic investment is the”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Number is the correct answer to “Atomic __________ of an element is a whole number.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Temperature is the correct answer to “Specific heat of an ideal gas depends upon its”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

None of these is the correct answer to “Rankine cycle comprises of two isothermal and two __________ processes.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Malleable is the correct answer to “__________ iron is produced by the annealing of white cast iron.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Production schedule is the correct answer to “Gantt charts are used for streamlining the”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Face centred cubic (fcc) is the correct answer to “Materials having __________ lattice structure are usually the most ductile.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Nichrome is the correct answer to “Copper is not present as an alloying constituent in”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

15% less is the correct answer to “Kinematic viscosity of water as compared to that of air is”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Proportional limit is the correct answer to “Area under the stress-strain curve upto the __________ is referred to as the modulus of resilience.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Hardness is the correct answer to “__________ test can be termed as the semi-distructive test.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

8.82 is the correct answer to “A 2 kg object weighs 1.8 kgf on a spring balance. The value of 'g' at that location in m/sec 2 is”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Zero is the correct answer to “The weight of a body at the centre of the earth is”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.

Cast iron is the correct answer to “Lead is poured into the joint between two __________ pipes.”. This question is standard in competitive examination syllabi for Chemical Engineering Basics.