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HAL Placement Papers - Chemical Engineering Questions



In the HAL Chemical Engineering section the students can expect multiple choice questions. The students are expected to select the right answer.

Here are few questions asked in the HAL written test of Chemical Engineering section. 

1. Why is Plasticisers added to paints?
(a) make it corrosion resistant.
(b) give elasticity & prevent cracking of the film. 
(c) increase atmospheric oxidation.
(d) make glossy surface

2. Which oil is preferred for manufacturing paint?
(a) Saturated oil 
(b) Non-drying oil
(c) Semi-drying oil
(d) Drying oil

3. What is the function of thinner in paint?
(a) accelerate the oxidation of oil.
(b) prevent gelling of the paint. 
(c) from a protective film.
(d) suspend pigments & dissolve film forming materials.

4. What varnish does not contain?
(a) anti-skimming agent. 
(b) thinner
(c) dryer
(d) pigment

5. Why are enamels used?
(a) are same as varnish. 
(b) give good glossy finish.
(c) are prepared from non-drying oil.
(d) do not contain pigment.

6. Why is SO2 bubbled through hot sugar cane juice?
(a) increase the crystal size. 
(b) increase its concentration.
(c) increase the amount of molasses. 
(d) act as an acidifying agent.

7. Which of the following is the starting material for the production of Molasses?
(a) massecuite 
(b) essential oil
(c) fatty acids
(d) Alcohol

8. What is the enzyme which converts starch into the disaccharides maltose?
(a) yeast 
(b) maltase
(c) diastase
(d) none of these

9. What is the Shape factor for a cylinder whose length equals its diameter?
(a) 1.0
(b) 0.5
(c) 1.5
(d) 2.0

10. What is the ratio of the actual mesh dimension of Taylor series to that of the next smaller screen?
(a) 1
(b) v2 
(c) 1.5
(d) 3

11. What is the opening of a 200 mesh screen Taylor series?
(a) 0.0047 cm 
(b) 0.0074 mm
(c) 0.0074 cm 
(d) 74 mili-microns

12. What is the ratio of the area of openings in one screen to that of the openings in the next smaller screen?
(a) 1.5
(b) 1
(c) 1.7
(d) none of these 

13.The Cumulative analysis for determining surface is more precise than differential analysis, because of the
(a) assumption that all particles in a single fraction are equal in size.
(b) fact that screening is more effective.
(c) assumption that all particles in a single fraction are equal in size.
(d) assumption that all particles in a single fraction are equal in size, is not needed.

14. The equivalent diameter of a particle is the diameter of the sphere having the same
(a) ratio of surface to volume as the actual volume. 
(b) ratio of volume to surface as the particle.
(c) volume as the particle.
(d) none of these

15. What is used for the coarse reduction of hard solids?
(a) compression 
(b) attrition
(c) impact 
(d) cutting

16. What is made of Soft & non-abrasive materials into fines?
(a) attrition 
(b) compression
(c) cutting
(d) none of these

17. What is the ratio of Crushing efficiency?
(a) surface energy created by crushing to the energy absorbed by the solid.
(b) energy absorbed by the solid to that fed to the machine.
(c) energy created by crushing.
(d) energy absorbed by the solid to the surface energy created by crushing.

18. What does the Rittinger's crushing law states?
(a) work required to form a particle of any size is proportional to the square of the surface to volume ratio of the product.
(b) work required to form a particle of a particular size is proportional to the square root of the surface to volume ratio of the product.
(c) work required in crushing is proportional to the new surface created. 
(d) for a given machine and feed, crushing efficiency is dependent on the size of the feed & product.

19. What does Bond crushing law states?
(a) calls for relatively less energy for the smaller product particles, than does the Rittinger law. 
(b) is less realistic in estimating the power requirements of commercial crushers.
(c) state that the work required to form particle of any size from very large feed is proportional to the square root of the volume to surface ratio of the product.
(d) states that the work required for the crushing is proportional to the new surface created.

20. How does work index defined?
(a) gross energy (k Wh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes through a 100 micron screen. 
(b) energy needed to crush one tonne of feed to 200 microns.
(c) energy (k Wh/ton of feed) needed to crush small feed to such a size that 80% of the product passes a 200 mesh screen.
(d) energy needed to crush one ton of feed to 100 microns.

21. The operating speed of a ball mill should be ......... the critical speed.
(a) much more than 
(b) less than
(c) at least equal to
(d) slightly more than

22. What is a fluid energy mill used for?
(a) cutting
(b) grinding
(c) ultragrinding 
(d) crushing

23. What does Wet grinding in a revolving mill do as compared to dry grinding?
(a) gives less wear on chamber walls
(b) requires more energy
(c) increases capacity 
(d) decreses handling of the product


24. The ideal pulp for the manufacture of paper should have high content of which material?
(a) ellulose 
(b) lignin
(c) Lignin and ellulose
(d) none of these

25. White cooking liquor consists of caustic soda, in Kraft process of paper manufacture
(a) sodium sulphide & sodium carbonate. 
(b) sodium sulphite & sodium carbonate.
(c) sodium sulphite & sodium sulphide.
(d) All of the three

26. Comparing sulphate process with sulphite process, what do we find in the later.
(a) both temperature & pressure in the former is less than that
(b) both temperature & pressure in the former is more than that 
(c) temperature is more in the former whereas pressure is more
(d) pressure is more in the former whereas temperature is less

27. What is Cooking liquor in case of sulphite process?
(a) sodium sulphite and sodium bisulphite. 
(b) magnesium sulphite and free SO2 in acid medium.
(c) magnesium sulphate and magnessium bicarbonate.
(d) none of these

28. From the following which is a high grade pulp?
(a) Sulphate pulp
(b) Mechanical pulp
(c) Rag pulp 
(d) Sulphite pulp

29. During manufacturing which of the following paper does not require filler?
(a) Blotting paper
(b) Writing paper
(c) Bond paper 
(d) Coloured paper

30. How is Bleaching of paper pulp done?
(a) bromine
(b) activated clay
(c) chlorine or chlorine dioxide 
(d) magnesium sulphite

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