Chemical Engineering Basics

271. For separating small pieces of metal from engine oil of a car, the best separating technique is the

1. Chromatography
2. Evaporation
3. Filtration
4. Fractional distillation

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272. For the irreversible reaction, C_a+ 2C = C_a C₂ , δ H°298 = - 60000 J . mole^-1 . If a system initially containing 2 moles of calcium, 3 moles of carbon and 1 mole of calcium carbide is allowed to react to completion, the heat evolved at 298 K will be

1. 30,000 J
2. 60,000 J
3. 90,000 J
4. 2,40,000 J

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273. For the Stoke's law to be valid in the case of a falling sphere in a fluid, the

1. Reynolds number (based on sphere diameter) should be < 1
2. Flow around the sphere should be in turbulent region
3. Sphere must be metallic
4. Fluid density should be constant

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274. For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm3) while the C.V. is same on weight basis (i.e., kcal/kg)?

1. Propane and acetylene
2. Propane and LPG
3. Sewage gas and gobar gas
4. B.F gas and coke oven gas

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275. Force between the molecules of the same substance is called __________ force.

1. Adhesive
2. Cohesive
3. Molecular
4. Vander Walls

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276. Friction factor for fluid flow in pipe does not depend upon the

1. Pipe length
2. Pipe roughness
3. Fluid density & viscosity
4. Mass flow rate of fluid

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277. Frother is added in the froth floatation cell used in ore beneficiation to stabilise the air bubbles (i.e., froth), which will hold the ore particles, but it does not affect the floatability of minerals. Which of the following is not used as a frother?

1. Cresylic acid
2. Xanthaies
3. Pine oil
4. All 'a' 'b' & 'c'

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278. Function of fusible plug in a boiler is to

1. Drain out water and sludge from the boiler during repair
2. Put off fire in the furnace when water level in the boiler falls to unsafe limit
3. Guard the boiler in case of abnormal rise in steam pressure
4. All (A), (B) & (C)

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279. Function of gear box is to

1. Reduce the speed
2. Obtain variable speed
3. Increase the speed
4. Produce high torque

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280. Gage pressure within a spherical droplet of a fluid is 'p'. What will be gage pressure within a bubble of the same size & of the same fluid?

1. p
2. 2 p
3. 0.5 p
4. 0.25 p

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