MCQOPTIONS
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MCQOPTIONS
This section includes 209 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
__Periclase refractory contains mainly__ |
| A. | CaO |
| B. | MgO |
| C. | Al2O‚ÇÉ |
| D. | SiO‚ÇÇ |
| Answer» C. Al2O‚Äö√á√â | |
| 102. |
__Porosity of silica bricks varies from __________ percent.__ |
| A. | 5 to 10 |
| B. | 20 to 30 |
| C. | 45 to 60 |
| D. | 60 to 75 |
| Answer» C. 45 to 60 | |
| 103. |
__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 | |
| 104. |
__Which is not a natural insulating material?__ |
| A. | Diatomaceous earth/kieselgur |
| B. | Asbestos |
| C. | Vermiculite |
| D. | None of these |
| Answer» E. | |
| 105. |
__Thermal diffusivity of a refractory brick is high, when its __________ is high.__ |
| A. | Density |
| B. | Specific heat |
| C. | Thermal conductivity |
| D. | None of these |
| Answer» D. None of these | |
| 106. |
__Which of the following bricks should not be used, if the furnace is to be used intermit-tantly?__ |
| A. | Firebricks |
| B. | Silica bricks |
| C. | Silicon carbide bricks |
| D. | Sillimanite |
| Answer» C. Silicon carbide bricks | |
| 107. |
__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 | |
| 108. |
__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 of the above |
| Answer» E. | |
| 109. |
__Rate of slag attack on refractories increases with rise in temperature due to the__ |
| A. | Decreased viscosity of slag |
| B. | Increased thermal conductivity of brick |
| C. | Oxidising condition in the furnace |
| D. | None of these |
| Answer» B. Increased thermal conductivity of brick | |
| 110. |
__Carbon refractories have very high__ |
| A. | Wetting characteristics |
| B. | Refractoriness |
| C. | Thermal conductivity |
| D. | Both B and C |
| Answer» E. | |
| 111. |
__Which of the following has the lowest electrical resistivity?__ |
| A. | Graphite |
| B. | Fireclay |
| C. | Alumina |
| D. | Zircon |
| Answer» B. Fireclay | |
| 112. |
__Silliminite (Al2O‚ÇÉ.SiO‚ÇÇ) refractory, which is a neutral refractory, is not used in__ |
| A. | Pottery furnace |
| B. | Glass melting furnace |
| C. | Crucibles |
| D. | Gas retorts |
| Answer» E. | |
| 113. |
__Refractories are dried in the__ |
| A. | Rotary kilns |
| B. | Tunnel kilns |
| C. | Sun |
| D. | None of these |
| Answer» C. Sun | |
| 114. |
__Spalling of a refractory means its__ |
| A. | Softening |
| B. | Fracture due to uneven expansion at high temperature |
| C. | Resistancce to compressive loads |
| D. | Resistance to chemical action of gases and molten fluxes |
| Answer» C. Resistancce to compressive loads | |
| 115. |
__High alumina refractory compared to fireclay bricks have__ |
| A. | Less load bearing capacity |
| B. | Less resistance to slag attack |
| C. | Low refractoriness |
| D. | High resistance to thermal shock and creep |
| Answer» E. | |
| 116. |
__Carborundum used for making crucibles for melting non-ferrous metals is chemically__ |
| A. | Silicon carbide |
| B. | Silicon nitride |
| C. | Crystalline magnesia |
| D. | Zirconium sulphate |
| Answer» B. Silicon nitride | |
| 117. |
__Firing of refractory brick is done to__ |
| A. | Dehydrate the dried refractory |
| B. | Develop stable mineral forms in them |
| C. | Form ceramic bonds necessary for development of high crushing strength in the finished product |
| D. | All of the above |
| Answer» E. | |
| 118. |
_Fireclay bricks are used in the$? |
| A. | Furnaces allowed to cool frequently |
| B. | Flues |
| C. | Chimney linings |
| D. | All of the above |
| Answer» E. | |
| 119. |
_Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the$? |
| A. | Hearth of the blast furnace |
| B. | Nuclear reactors, missiles & space crafts |
| C. | Insulation of high temperature furnaces |
| D. | Roof of electric furnaces |
| Answer» C. Insulation of high temperature furnaces | |
| 120. |
_Which of the following is not a high alumina refractory material?$? |
| A. | Kyanite |
| B. | Sillimanite |
| C. | Diaspore |
| D. | Periclase |
| Answer» E. | |
| 121. |
_Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of __________ °C.$? |
| A. | 770 |
| B. | 570 |
| C. | 270 |
| D. | 70 |
| Answer» D. 70 | |
| 122. |
_High density refractory bricks have lower$? |
| A. | Spalling resistance |
| B. | Thermal conductivity |
| C. | Fusion point |
| D. | Slag penetration resistance |
| Answer» B. Thermal conductivity | |
| 123. |
_Refractory materials are never used in the construction of$? |
| A. | Segar cones |
| B. | Orton cones |
| C. | Pressure vessels |
| D. | Ovens & retorts |
| Answer» D. Ovens & retorts | |
| 124. |
_Which is the most stable crystalline form of silica at room temperature?$? |
| A. | Quartz |
| B. | Cristobalite |
| C. | Tridymite |
| D. | None of these |
| Answer» B. Cristobalite | |
| 125. |
_Refractoriness under loads (RUL) is quite close to the fusion temperature (PCE) for __________ bricks.$? |
| A. | Fireclay |
| B. | Silica |
| C. | Dolomite |
| D. | Very low alumina |
| Answer» C. Dolomite | |
| 126. |
_Chrome magnesite is not used in the$? |
| A. | Inner lining of L.D. converter |
| B. | Aluminium melting furnaces |
| C. | Wear out lining of steel melting furnaces |
| D. | All of the above |
| Answer» D. All of the above | |
| 127. |
_Colour of fireclay bricks is$? |
| A. | Light buff to reddish buff |
| B. | Yellow |
| C. | Black |
| D. | None of these |
| Answer» B. Yellow | |
| 128. |
_Vacuum steel degassing units are lined with$? |
| A. | Silica bricks |
| B. | Low duty firebricks |
| C. | High alumina bricks |
| D. | Graphite blocks |
| Answer» D. Graphite blocks | |
| 129. |
_Chemically, mullite refractories is$? |
| A. | 3Al2O‚ÇÉ.2SiO‚ÇÇ |
| B. | Al2O‚ÇÉ |
| C. | ZrSO‚ÇÑ |
| D. | ThO‚ÇÇ |
| Answer» B. Al2O‚Äö√á√â | |
| 130. |
_Which is not a basic refractory?$? |
| A. | Chrome magnesite |
| B. | Magnesite |
| C. | Dolomite |
| D. | Silicon carbide |
| Answer» E. | |
| 131. |
_Grog addition in fireclay during brick manufacture is done to$? |
| A. | Reduce its shrinkage on heating |
| B. | Impart greater spalling resistance |
| C. | Enhance the strength of fired refractories |
| D. | All of the above |
| Answer» E. | |
| 132. |
_Spray test determines the __________ of refractories.$? |
| A. | Resistance to slag penetration |
| B. | Resistance to CO attack |
| C. | RUL |
| D. | Permanent linear change |
| Answer» B. Resistance to CO attack | |
| 133. |
_Ferromagnetic ceramic material is not used in the$? |
| A. | Thermal insulation |
| B. | Transformers |
| C. | Magnetic switches |
| D. | Television sets |
| Answer» B. Transformers | |
| 134. |
_Panel test determines the __________ of refractories.$? |
| A. | Fusion point |
| B. | Spalling resistance |
| C. | Slag penetration resistance |
| D. | Refractoriness under load (RUL) |
| Answer» C. Slag penetration resistance | |
| 135. |
_Ganister is a source of the$? |
| A. | Silica |
| B. | Periclase |
| C. | Lime |
| D. | None of these |
| Answer» B. Periclase | |
| 136. |
Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material?$? |
| A. | Aluminium phosphate |
| B. | Water |
| C. | Lime |
| D. | Plaster of paris |
| Answer» C. Lime | |
| 137. |
Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of$? |
| A. | Fireclay |
| B. | Silicon carbide |
| C. | Corrundum |
| D. | Siliceous fireclay |
| Answer» C. Corrundum | |
| 138. |
Thoria is an expensive refractory material and is radioactive in nature. Thorium oxide is used in the manufacture of$? |
| A. | Segar cones |
| B. | Muffles for muffle furnaces |
| C. | Insulating bricks |
| D. | Crucibles used for melting of high purity metals |
| Answer» E. | |
| 139. |
Which is required in an insulating refractory?$? |
| A. | High thermal conductivity |
| B. | Low porosity |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» E. | |
| 140. |
Which one contains maximum percentage of Al2O‚ÇÉ ?$? |
| A. | Firebrick |
| B. | Sillimanite |
| C. | Magnesite |
| D. | Aluminous firebrick |
| Answer» C. Magnesite | |
| 141. |
Roof of a basic open hearth furnace is lined with __________ bricks.$? |
| A. | Silica |
| B. | Fireclay |
| C. | Dolomite |
| D. | Magnesite |
| Answer» B. Fireclay | |
| 142. |
Which of the following bricks has the most close values of RUL and PCE?$? |
| A. | Silica bricks |
| B. | Fireclay bricks |
| C. | High alumina bricks |
| D. | Tar dolomite bricks |
| Answer» B. Fireclay bricks | |
| 143. |
Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as __________ percent.$? |
| A. | 10 |
| B. | 15 |
| C. | 20 |
| D. | 30 |
| Answer» E. | |
| 144. |
Furnace atmosphere for softening temperature determination of refractories (in which segar cones are placed) should be$? |
| A. | Oxidising |
| B. | Neutral |
| C. | Either A or B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 145. |
Test piece for determination of RUL of a refractory is heated in a/an$? |
| A. | Oxidising atmosphere |
| B. | Reducing atmosphere |
| C. | Electric furnace |
| D. | Neutral atmosphere |
| Answer» D. Neutral atmosphere | |
| 146. |
Fusion point of a basic refractory material is$? |
| A. | Reduced by the addition of acid oxides |
| B. | Increased by the addition of acid oxides |
| C. | Not affected by the addition of acid oxides |
| D. | Always less than 1000°C |
| Answer» B. Increased by the addition of acid oxides | |
| 147. |
High thermal conductivity of a refractory material is not important, when it is to be used in the$? |
| A. | Coke oven regenarators |
| B. | Muffle furnace |
| C. | Blast furnace |
| D. | Recuperators |
| Answer» D. Recuperators | |
| 148. |
Refractory castables are used for$? |
| A. | Producing monolithic linings |
| B. | Patch work |
| C. | Minimising the number of joints in the structure |
| D. | All of the above |
| Answer» E. | |
| 149. |
SiO‚ÇÇ percentage in firebrick is about$? |
| A. | 35-40 |
| B. | 55-60 |
| C. | 80-85 |
| D. | >94 |
| Answer» C. 80-85 | |
| 150. |
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 of the above |
| Answer» E. | |