Chemical Engineering Basics

351. In practice, the compression ratio of compression-ignition (CI) engine ranges from

  1. 15 to 25
  2. 5 to 10
  3. 40 to 55
  4. 60 to 70

Correct answer: (A)
15 to 25

352. In the acid Bessemer process, the hot metal should have the following composition.

  1. S < 0.05% and P < 0.05%
  2. S < 0.05% and P < 1.5%
  3. S < 0.05% and P > 1.5%
  4. S > 1.5% and P < 0.05%

Correct answer: (A)
S < 0.05% and P < 0.05%

353. In the Bayer's process, bauxite is digested under pressure using

  1. H2SO4
  2. NaOH
  3. NH3
  4. HCl

Correct answer: (B)
NaOH

354. In the blast furnace, incorporation of water vapour in the blast gives the following effect.

  1. Increases the reducing potential of the gas
  2. Increases the flame temperature
  3. No significant change occurs
  4. Increases the hydrogen content in the metal

Correct answer: (A)
Increases the reducing potential of the gas

355. In the diving apparatus, helium is used along with oxygen, because it is

  1. Easily available
  2. Not soluble in blood at high pressure
  3. Lighter than nitrogen
  4. Completely miscible with oxygen

Correct answer: (B)
Not soluble in blood at high pressure

356. In the formation of cermets, the ratio of ceramic material to metallic material is usually 80:20. Which of the following is a cermet?

  1. Zirconia
  2. Alumina
  3. Bakelite
  4. Tungsten carbide

Correct answer: (D)
Tungsten carbide

357. In the X-ray radiography technique, the tube voltage for thicker plates as compared to thin plates, should be

  1. Higher, as it gives higher wavelength
  2. Lower, as it gives higher wavelength
  3. Higher, as it gives shorter wavelength
  4. Lower, as it gives shorter wavelength

Correct answer: (C)
Higher, as it gives shorter wavelength

358. In TIG welding, thoriated tungsten electrodes are used, because it

  1. Has higher current carrying capacity
  2. Has better electron emissivity
  3. Is stronger than ordinary tungsten
  4. Is easy to prepare

Correct answer: (B)
Has better electron emissivity

359. In troposphere (the weather domain), the temperature 't' at height 'h' above the sea level in metres is given by (where, temperature at sea level is 15°C and t is in °C.)

  1. t = 15 - 0.0065 h
  2. t = 15 + 0.0065 h
  3. t = 0.0035 h - 15
  4. t = 15 - 0.0035 h

Correct answer: (A)
t = 15 - 0.0065 h

360. Increase in temperature, in general results in the

  1. Decrease in the viscosities of both liquids & gases
  2. Increase in the viscosities of both liquids & gases
  3. Increase in the viscosity of liquids and decrease in that of gases
  4. Decrease in the viscosity of liquids and increase in that of gases

Correct answer: (D)
Decrease in the viscosity of liquids and increase in that of gases

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