261. Naphthalene is used for making
Insecticides (e.g. moth balls)
Unsaturated polyesters
Drug intermediates e.g. β-naphthol
All of the above
✅ The correct answer is option D.
Fuel and Combustion MCQs
262. Net calorific value is the gross calorific value less the __________ heat of water in the product of combustion when cooled to 15°C.
Sensible
Latent
Sensible and latent
None of these
✅ The correct answer is option C.
263. Combustion of pulverised fuel
Requires larger combustion chamber than rich gaseous fuel
In a metallurgical furnace does not contaminate the product in the furnace by ash from fuel
Suppresses the discharge of fine dust and grit into atmosphere
All of the above
✅ The correct answer is option A.
264. Degree of carbonisation of coal during coke making can be roughly judged by the __________ of the coke produced.
Colour
Moisture content
Ash content
Volatile matter
✅ The correct answer is option D.
265. The cooling medium used in dry quenching of coke is
Nitrogen
Air
Phenolic water
Carbon dioxide
✅ The correct answer is option A.
266. In low temperature carbonisation (as compared to high temperature carbonisation) of coal
Ammonia yield is more
Aliphatic tar is produced
Free carbon in tar is more
All of the above
✅ The correct answer is option B.
267. Beehive coke oven
Facilitates by-products recovery
Takes 2-3 days for coking of coal but requires no external fuel for heating
Gives larger yield of coke (around 85%) as compared to by-product ovens
Produces coke with very poor strength
✅ The correct answer is option B.
268. Softening temperature of coal ash is a measure of the __________ of coal.
Caking tendency
Coking tendency
Clinkering tendency
Size stability
✅ The correct answer is option C.
269. Safe condition for storage of high V.M. bituminous coal is that
Height of the coal heap should be < 3 metres
Maximum 200 tons should be stored in a heap
Both A and B
Neither A nor B
✅ The correct answer is option C.
270. Which of the following is a lean fuel gas?
Coke oven gas
LPG
Blast furnace gas
Natural gas
✅ The correct answer is option C.