MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 568 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
Which is the stable form of silica between 1470°C and the melting point 1713°C ? |
| A. | Cristobalite |
| B. | Tridymite |
| C. | Quartz |
| D. | None of these |
| Answer» B. Tridymite | |
| 352. |
Which of the following is not a high alumina refractory material? |
| A. | Kyanite |
| B. | Sillimanite |
| C. | Diaspore |
| D. | Periclase |
| Answer» E. | |
| 353. |
Highest melting (m.p = 3070°C) oxide refractory is |
| A. | Alumina |
| B. | Thoria |
| C. | Zirconia |
| D. | Magnesia |
| Answer» C. Zirconia | |
| 354. |
Which of the following is not an acidic refractory ? |
| A. | Silica bricks |
| B. | Fireclay bricks |
| C. | Bauxite bricks |
| D. | Magnesia bricks |
| Answer» E. | |
| 355. |
Cold crushing strength of fireclay bricks is about __________ kgf/cm2. |
| A. | 50-100 |
| B. | 100-150 |
| C. | 200-400 |
| D. | 500-1000 |
| Answer» D. 500-1000 | |
| 356. |
Fireclay bricks are never used in the |
| A. | beehive oven |
| B. | coke oven walls |
| C. | zinc roaster |
| D. | lead blast furnace |
| Answer» C. zinc roaster | |
| 357. |
Tar bonded dolomite bricks |
| A. | are stored under controlled temperature & humidity to avoid hydration. |
| B. | are used in outer lining of L.D. converters. |
| C. | have poorer hydration resistance than pitch bonded bricks. |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 358. |
Basic bricks are not made of |
| A. | fireclay |
| B. | magnesite |
| C. | foresterite |
| D. | chromite |
| Answer» B. magnesite | |
| 359. |
Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material? |
| A. | aluminium phosphate |
| B. | water |
| C. | lime |
| D. | plaster of paris |
| Answer» C. lime | |
| 360. |
Chrome magnesite is not used in the |
| A. | inner lining of L.D. converter. |
| B. | aluminium melting furnaces. |
| C. | wear out lining of steel melting furnaces. |
| D. | all (a), and (b) and (c) |
| Answer» D. all (a), and (b) and (c) | |
| 361. |
Conversion of silica mineral to cristobalite is accompanied by reduction in its |
| A. | volume |
| B. | specific gravity |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» C. both (a) & (b) | |
| 362. |
Spalling resistance of a refractory can not be increased by |
| A. | increasing its porosity. |
| B. | using a coarser grog during its manufacture. |
| C. | decreasing its thermal co-efficient of expansion. |
| D. | making it denser. |
| Answer» E. | |
| 363. |
Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as __________ percent. |
| A. | 55 |
| B. | 70 |
| C. | 80 |
| D. | 90 |
| Answer» E. | |
| 364. |
Pure oxide refractories are generally monocrystaliine in nature and are self bonded __________ bricks are generally used as moderator in nuclear reactors. |
| A. | Beryllia |
| B. | Carborundum |
| C. | Corundum |
| D. | Thoria |
| Answer» B. Carborundum | |
| 365. |
Silica bricks are never used for lining the |
| A. | beehive coke ovens. |
| B. | by-product coke ovens. |
| C. | dome of blast furnace stoves. |
| D. | roof of open hearth furnace. |
| Answer» B. by-product coke ovens. | |
| 366. |
Addition of grog in fireclay brick during its manufacture is advantageous, because it results in |
| A. | less shrinkage in heating, decreased apparent porosity & increased specific gravity. |
| B. | high strength & thermal spalling resistance. |
| C. | less addition of water to get a workable plasticity & lesser time required for drying the raw refractories and hence increased rate of production. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 367. |
High refractorinness of refractory bricks means, that it has a |
| A. | high spalling resistance. |
| B. | low spalling resistance. |
| C. | high resistance to fusion. |
| D. | low porosity. |
| Answer» D. low porosity. | |
| 368. |
The highest melting pure oxide (m.p. > 3000°C)is$ |
| A. | thoria |
| B. | alumina |
| C. | beryllia |
| D. | zirconia |
| Answer» B. alumina | |
| 369. |
Faster rate of drying of moulded refractories results in high __________ of refractories. |
| A. | green strength |
| B. | voids |
| C. | shrinkage |
| D. | both (b) and (c) |
| Answer» E. | |
| 370. |
Thermal spalling mainly occurs during __________ of furnaces. |
| A. | cooling down |
| B. | warming up |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 371. |
Highest melting (m.p = 3070°C) oxide refractory is$ |
| A. | alumina |
| B. | thoria |
| C. | zirconia |
| D. | magnesia |
| Answer» C. zirconia | |
| 372. |
__________ nozzles are used in continuous casting of steel, |
| A. | Zircon |
| B. | Thoria |
| C. | Carborundum |
| D. | Beryllia |
| Answer» B. Thoria | |
| 373. |
Silicon carbide refractories are used in the |
| A. | muffle furnace |
| B. | zinc smelting furnace |
| C. | ceramic recuperators |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 374. |
Porosity of fireclay refractories is __________ percent. |
| A. | 43743 |
| B. | 45931 |
| C. | 25-35 |
| D. | 35-50 |
| Answer» C. 25-35 | |
| 375. |
Lower wall courses of soaking pits are made of __________ bricks to avoid the action of molten slag & scale. |
| A. | chrome or magnesite |
| B. | silicon carbide |
| C. | silica |
| D. | lowduty fireclay |
| Answer» B. silicon carbide | |
| 376. |
Magnesite chrome bricks are used in the |
| A. | roof lining of basic open hearth & other basic furnaces. |
| B. | reheating furnaces. |
| C. | soaking pits. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 377. |
Which of the following impurities reduces the refractoriness of magnesite bricks ? |
| A. | Al2O3 |
| B. | CaO |
| C. | SiO2 |
| D. | all (a), (b) & (c) |
| Answer» E. | |
| 378. |
Which is a basic refractory ? |
| A. | Fireclay |
| B. | Silica |
| C. | Chrome magnesite |
| D. | None of these |
| Answer» D. None of these | |
| 379. |
With decrease in porosity, the __________ of the refractories decreases. |
| A. | strength |
| B. | thermal conductivity |
| C. | spalling resistance |
| D. | none of these |
| Answer» D. none of these | |
| 380. |
Which one contains maximum percentage of Al2O3 ? |
| A. | Firebrick |
| B. | Sillimanite |
| C. | Magnesite |
| D. | Aluminous firebrick |
| Answer» C. Magnesite | |
| 381. |
Which is not a natural insulating material? |
| A. | Diatomaceous earth/kieselgur |
| B. | Asbestos |
| C. | Vermiculite |
| D. | None of these |
| Answer» E. | |
| 382. |
Slide gates in teeming laddie used for steel pouring in ingot moulds is lined with __________ bricks. |
| A. | bakelite impregnated or fused periclase |
| B. | silica |
| C. | semi-silica |
| D. | fireclay |
| Answer» B. silica | |
| 383. |
Chrome magnesite brick is not used for lining the |
| A. | hearth of soaking pits. |
| B. | bottom hearth of reheating furnace. |
| C. | coke oven regenerator. |
| D. | burning zone of limestone rotary kilns. |
| Answer» D. burning zone of limestone rotary kilns. | |
| 384. |
High thermal conductivity of a refractory material is not important, when it is to be used in the |
| A. | coke oven regenarators |
| B. | muffle furnace |
| C. | blast furnace |
| D. | recuperators |
| Answer» D. recuperators | |
| 385. |
Carbon refractory blocks |
| A. | are wetted by molten iron. |
| B. | are used in the hearth of blast furnace. |
| C. | are acidic in nature. |
| D. | all (a), (b) and (c). |
| Answer» C. are acidic in nature. | |
| 386. |
Porosity is induced in insulating refractories by adding |
| A. | powdered naphthalene. |
| B. | ammonium chloride/sulphate. |
| C. | calcium phosphate. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 387. |
Which refractory must have controlled atmosphere (temperature and humidity) for its safe storage ? |
| A. | Tar bonded dolomite bricks |
| B. | Fireclay bricks |
| C. | Mullite bricks |
| D. | Magnesite bricks |
| Answer» B. Fireclay bricks | |
| 388. |
Chrome magnesite bricks are used in the |
| A. | side walls of soaking pits and arc furnaces. |
| B. | copper melting furnaces & converters. |
| C. | burner block of glass tanks. |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 389. |
Refractory materials are never used in the construction of |
| A. | segar cones |
| B. | orton cones |
| C. | pressure vessels |
| D. | ovens & retorts |
| Answer» D. ovens & retorts | |
| 390. |
Periclase refractory contains mainly |
| A. | CaO |
| B. | MgO |
| C. | Al2O3 |
| D. | SiO2 |
| Answer» C. Al2O3 | |
| 391. |
Which of the following is not a high alumina refractory material ? |
| A. | Kyanite |
| B. | Sillimanite |
| C. | Diaspore |
| D. | Periclase |
| Answer» E. | |
| 392. |
Natural silica |
| A. | mainly contains quartz. |
| B. | is not stable at high temperature. |
| C. | transforms to other allotropic forms i.e tridymite and cristoballite involving very high volume changes. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 393. |
Machine moulding of dry mixture of refractories requires a pressure of the order of __________ kg/cm2. |
| A. | 10 |
| B. | 100 |
| C. | 500 |
| D. | 1000 |
| Answer» E. | |
| 394. |
Furnace atmosphere for softening temperature determination of refractories (in which segar cones are placed) should be |
| A. | oxidising |
| B. | neutral |
| C. | either (a) or (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 395. |
Graphite or carbon refractories |
| A. | exihibit wetting characteristics. |
| B. | should be used in neutral or reducing atmosphere. |
| C. | exhibit high shrinkage on thermal treatment. |
| D. | are not resistant to corrosion by slag. |
| Answer» C. exhibit high shrinkage on thermal treatment. | |
| 396. |
Ferromagnetic ceramic material is not used in the |
| A. | thermal insulation |
| B. | transformers |
| C. | magnetic switches |
| D. | television sets |
| Answer» B. transformers | |
| 397. |
silicon carbide refractories have very low |
| A. | refractoriness (< 1700°C). |
| B. | thermal conductivity. |
| C. | resistance to thermal shock. |
| D. | none of these. |
| Answer» E. | |
| 398. |
Fireclay refractories |
| A. | are not resistant to the action of basic slags. |
| B. | combine with salts (e.g. chlorides sulphates etc.) & bases (e.g. lime, magnesia etc.) forming fusible aluminates silicates etc. |
| C. | shrink during firing |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 399. |
Permeability of bricks is a measure of the |
| A. | refractoriness. |
| B. | melting point. |
| C. | rate at which a fluid will pass through the pores. |
| D. | expansion during heating. |
| Answer» D. expansion during heating. | |
| 400. |
With increase in the alumina content in firebricks, its fusion point (refractoriness) |
| A. | decreases linearly |
| B. | remains unchanged |
| C. | increases |
| D. | decreases |
| Answer» D. decreases | |