MCQOPTIONS
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MCQOPTIONS
This section includes 408 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
Fusion point of coal ash generally varies from 1000 to 1700° C. Ash having fusion point less than _______________ °C is liable to form clinker? |
| A. | 1100 |
| B. | 1250 |
| C. | 1350 |
| D. | 1400 |
| Answer» B. 1250 | |
| 252. |
Furnace oil consumption in a furnace for a given duty employing preheated combination air (at 300°) may be reduced by about ______________ percent as compared to the use of atmospheric combustion air? |
| A. | 5 |
| B. | 10 |
| C. | 20 |
| D. | 35 |
| Answer» D. 35 | |
| 253. |
Function of secondary air in pulverised coal firing is to_________________? |
| A. | Transport the coal to the burner |
| B. | Dry the coal |
| C. | Ensure efficient burning of coal around the burner |
| D. | Reduce primary air requirement |
| Answer» D. Reduce primary air requirement | |
| 254. |
Fuel gases containing hydrocarbons (e.g. coke oven gas) are not preheated before burning, mainly because __________________? |
| A. | The hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot |
| B. | It reduces its calorific value tremendously |
| C. | It reduces its flame temperature tremendously |
| D. | There are chances of explosion during preheating |
| Answer» B. It reduces its calorific value tremendously | |
| 255. |
Fuel for a nuclear reactor (thermal) is ____________________? |
| A. | Uranium |
| B. | Plutonium |
| C. | Radium |
| D. | None of these |
| Answer» B. Plutonium | |
| 256. |
Fuel for a fast breeder nuclear reactor is____________________? |
| A. | Plutonium |
| B. | Uranium |
| C. | Radium |
| D. | Neptunium |
| Answer» B. Uranium | |
| 257. |
Fuel consumption in coke making can be reduced by___________________? |
| A. | Preheating, blending and de-ashing the coal |
| B. | Stamped charging of coal |
| C. | Dry quenching of coke |
| D. | All A., B. and C. |
| Answer» E. | |
| 258. |
Fuel combustion is never cent per cent efficient due to___________________? |
| A. | Incomplete combustion |
| B. | Dry gas/stack gas loss |
| C. | Moisture loss |
| D. | All A., B. and C. |
| Answer» E. | |
| 259. |
‘Fuel’ can be defined as a substance which produces heat by___________________? |
| A. | Combustion |
| B. | Nuclear fission |
| C. | Nuclear fusion |
| D. | All A., B. & C. |
| Answer» E. | |
| 260. |
Froth floatation is used for_________________? |
| A. | Washing fine coal dust (< 0.5 mm size) |
| B. | Washing lump coal (> 80 mm size) |
| C. | Removing ash from the coal based on difference in specific gravity of coal and ash |
| D. | All A., B. and C. |
| Answer» B. Washing lump coal (> 80 mm size) | |
| 261. |
Fossil fuels mean___________________? |
| A. | Solid fuels |
| B. | Liquid fuels |
| C. | Those fuels which are found in the crust of earth |
| D. | Premature fuels with low calorific value |
| Answer» D. Premature fuels with low calorific value | |
| 262. |
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) ? |
| A. | Propane and acetylene |
| B. | Propane and LPG |
| C. | Sewage gas and gobar gas |
| D. | B.F. gas and coke oven gas |
| Answer» B. Propane and LPG | |
| 263. |
For the case of a fuel gas undergoing combustion with air, if the air/fuel ratio is increased, the adiabatic flame temperature will_____________________? |
| A. | Increase |
| B. | Decrease |
| C. | Increase or decrease depending on the fuel type |
| D. | Not change |
| Answer» C. Increase or decrease depending on the fuel type | |
| 264. |
For maximum discharge through a chimney, its height should be___________________? |
| A. | 200 meters |
| B. | Infinitely long |
| C. | More than 105.7 metres |
| D. | Equal to the height of the hot gas column producing draught |
| Answer» E. | |
| 265. |
For long flame and easy ignition, the coal used should have_________________? |
| A. | High volatile matter |
| B. | Low ash |
| C. | High calorific value |
| D. | High ash |
| Answer» B. Low ash | |
| 266. |
For every 10% increase in the excess air; the fuel consumption increases by _______________ percent? |
| A. | 0.1 |
| B. | 0.2 |
| C. | 0.5 |
| D. | 1.0 |
| Answer» B. 0.2 | |
| 267. |
Flue gas obtained on complete combustion of pure acetylene (a hydrocarbon fuel) will contain __________________? |
| A. | CO |
| B. | CO2 |
| C. | H2O |
| D. | Both B. & C. |
| Answer» E. | |
| 268. |
Flue gas from the heating chamber of by product coke ovens is removed by________________? |
| A. | Forced draft fan |
| B. | Induced draft fan |
| C. | Steam ejector |
| D. | Natural draft |
| Answer» E. | |
| 269. |
Flue gas discharge velocity through chimney of a big thermal power plant may be around ________________ m/sec? |
| A. | 0.5 |
| B. | 10 |
| C. | 50 |
| D. | 500 |
| Answer» C. 50 | |
| 270. |
Fixed carbon in coal is defined as______________________? |
| A. | That present in volatile matters |
| B. | The total quantity of carbon present in the coal |
| C. | Hundred minus the percentage of volatile matter, ash and moisture |
| D. | The one which is present in the residue after combustion |
| Answer» D. The one which is present in the residue after combustion | |
| 271. |
Fischer-Tropsch method aims at the ______________________? |
| A. | Gasification of coal |
| B. | Synthesis of gasoline (from water gas) |
| C. | Hydrogenation of coal to produce gasoline |
| D. | None of these |
| Answer» C. Hydrogenation of coal to produce gasoline | |
| 272. |
‘Fat’ coal means a coal having ___________________? |
| A. | Low calorific value |
| B. | High volatile matter |
| C. | Low ash content |
| D. | Non smoking tendency |
| Answer» C. Low ash content | |
| 273. |
‘Fat coals’ are those coals which have very high____________________? |
| A. | Caking capacity |
| B. | Volatile matter content |
| C. | Fusion point of its ash |
| D. | Inherent moisture content |
| Answer» B. Volatile matter content | |
| 274. |
Explosion limit of blast furnace gas is 37 to 71% gas in gas-air mixture. It means that the blast furnace gas will explode when burnt in a confined space, if its concentration in the gas-air mixture is _______________ percent? |
| A. | 71% |
| B. | In between 37 & 71% |
| C. | None of these |
| Answer» C. None of these | |
| 275. |
Eschka mixture, which is used for the determination of sulphur in coal, is a mixture of _____________________? |
| A. | MgO & Na2CO3 |
| B. | MgSO4 & BaCl2 |
| C. | BaSO4 & NaCl |
| D. | MgCO3 & NaCl |
| Answer» B. MgSO4 & BaCl2 | |
| 276. |
Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of__________________? |
| A. | Less air for combustion |
| B. | Correct amount of air for combustion |
| C. | Too much air for combustion |
| D. | Pulverised coal in boilers |
| Answer» D. Pulverised coal in boilers | |
| 277. |
Efficient burning of anthracite coal requires______________________? |
| A. | Low preheat of air |
| B. | Fine grinding |
| C. | High excess air |
| D. | All A., B. and C |
| Answer» C. High excess air | |
| 278. |
Efficiency of the combustion of a fuel is judged by the ______________ the flue gas? |
| A. | % of CO2 in |
| B. | % of O2in |
| C. | Temperature of |
| D. | Colour of |
| Answer» C. Temperature of | |
| 279. |
Dust content in raw blast furnace gas is about _______________ gm/Nm3; hence it is cleaned to the dust level of about < 10 mg /Nm3 before use? |
| A. | 15-30 |
| B. | 1-2 |
| C. | 70-100 |
| D. | 150-200 |
| Answer» B. 1-2 | |
| 280. |
During the carbonisation of coal__________________? |
| A. | All tar is evolved at 700°C |
| B. | Hard semi-coke starts shrinking at 600°C |
| C. | All A., B. and C. |
| Answer» D. | |
| 281. |
During its calorific value determination by bomb calorimeter, coal is combusted by _________________? |
| A. | Air |
| B. | Oxygen |
| C. | Oxygen enriched air |
| D. | None of these |
| Answer» C. Oxygen enriched air | |
| 282. |
During combustion of gaseous fuels, deficiency of air_________________? |
| A. | Lengthens the flame |
| B. | Tends to shorten the flame |
| C. | Does not affect the flame length |
| D. | Increases the flame temperature |
| Answer» B. Tends to shorten the flame | |
| 283. |
During combustion of coal on grate, clinker formation is increased by the___________________? |
| A. | Use of thick fire bed |
| B. | Low fusion point of ash (< 1100° C) |
| C. | Use of preheated primary air |
| D. | All A., B. & C. |
| Answer» E. | |
| 284. |
During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the____________________? |
| A. | Incomplete combustion |
| B. | Complete combustion |
| C. | High oxygen in flue gas |
| D. | None of these |
| Answer» C. High oxygen in flue gas | |
| 285. |
During coking of coal, the ash content (percentage)________________? |
| A. | Increases |
| B. | Decreases |
| C. | Remain constant |
| D. | None of these |
| Answer» B. Decreases | |
| 286. |
During coal carbonisation process, the conversion of semi-coke to coke is accompanied by an increase in the _______________ of the mass? |
| A. | Density |
| B. | Porosity |
| C. | Electrical resistivity |
| D. | None of these |
| Answer» B. Porosity | |
| 287. |
Dry air requirement for burning 1 Nm3 of CO to CO2 may be around _______________ Nm3 ? |
| A. | 2.4 |
| B. | 1.75 |
| C. | 0.87 |
| D. | 11.4 |
| Answer» B. 1.75 | |
| 288. |
Dry air required to burn 1 kg of carbon completely may be around ______________ kg? |
| A. | 11 |
| B. | 2 |
| C. | 20 |
| D. | 38 |
| Answer» B. 2 | |
| 289. |
Desirable “Micum Index” values of metallurgical coke are ___________________? |
| A. | M40 > 78% and M10 < 10% |
| B. | M40 > 4% and M10 10% and M10 98% and M10 < 2% |
| Answer» B. M40 > 4% and M10 10% and M10 98% and M10 < 2% | |
| 290. |
Degree of carbonisation of coal during coke making can be roughly judged by the ______________ of the coke produced? |
| A. | Colour |
| B. | Moisture content |
| C. | Ash content |
| D. | Volatile matter |
| Answer» E. | |
| 291. |
Deficiency of combustion air during combustion of a gaseous fuel_____________________? |
| A. | Lengthens the flame |
| B. | Causes heat loss of fuel by its partial combustion |
| C. | Both A. & B. |
| D. | Shortens the flame |
| Answer» D. Shortens the flame | |
| 292. |
C.V. (kcal/Nm3) of gaseous fuels _____________ with increase in molecular weight? |
| A. | Decreases |
| B. | Increases |
| C. | Remain constant |
| D. | May increase or decrease, depends on combustibles |
| Answer» E. | |
| 293. |
Critical Air Blast (CAB) value of coke is a direct measure of its__________________? |
| A. | Reactivity |
| B. | Hardness |
| C. | Strength |
| D. | None of these |
| Answer» B. Hardness | |
| 294. |
Correct viscosity of furnace oil at the burner tip for proper atomisation is about 25 centistokes. To reduce the viscosity of high viscosity furnace oil (250 centistokes) to the correct atomisation viscosity (i.e. 25 cst), it should be preheated to about ______________°C? |
| A. | 70 |
| B. | 85 |
| C. | 105 |
| D. | 145 |
| Answer» D. 145 | |
| 295. |
Compound coke ovens are those which can be heated by __________________? |
| A. | Both steam and electrical power |
| B. | Lean gas (e.g., B.F. gas) |
| C. | Rich gas (e.g., coke oven gas) |
| D. | Both B. and C. |
| Answer» E. | |
| 296. |
Commercial production of petrol from coal (as practised in a factory at Sasol in South Africa) is done by the ________________ of coal? |
| A. | Hydrogenation |
| B. | Gasification |
| C. | Carbonisation |
| D. | None of these |
| Answer» B. Gasification | |
| 297. |
Combustion reaction of fuels is a/an ______________ reaction? |
| A. | Auto catalytic |
| B. | Exothermic |
| C. | Endothermic |
| D. | None of these |
| Answer» C. Endothermic | |
| 298. |
Combustion of pulverised coal as compared to that of lump coal ________________? |
| A. | Develops a non-luminous flame |
| B. | Develops a low temperature flame |
| C. | Can be done with less excess air |
| D. | Provides a lower rate of heat release |
| Answer» D. Provides a lower rate of heat release | |
| 299. |
Coking time in narrow by-product coke ovens is around ______________ hours? |
| A. | 18 |
| B. | 48 |
| C. | 8 |
| D. | 80 |
| Answer» B. 48 | |
| 300. |
Coking time in beehive coke oven is about ___________________? |
| A. | 12 hours |
| B. | 2-3 days |
| C. | One week |
| D. | Two weeks |
| Answer» C. One week | |