Electrolytic reduction cell used for conversion of calcined Al2O3to Al is a carbon lined furnace operating at 800-900 °C. The purpose of electric current supplied to the furnace is to
(A) Achieve very high purity of aluminium (99.9%)
(B) Keep the electrolyte in liquid condition by the generation of heat (C) Electrolytically dissociate alumina
(D) Both (B) & (C)

1 Answer

Answer :

(D) Both (B) & (C)

Related questions

Description : Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at __________ °C in absence of air. (A) 50-80 (B) 250-400 (C) 1000-1200 (D) 800-900

Last Answer : (B) 250-400

Description : The metallic aluminium is obtained from pure alumina in the presence of fused cryolite by (A) Electrolysis (B) Electrolytic reduction (C) Electrolytic oxidation (D) None of these

Last Answer : (B) Electrolytic reduction

Description : (A) Alumina has hgih condutivity (R ) The mixture of alumia and cryolite is used for electrolytic reduction in order to extract aluminium

Last Answer : (A) Alumina has hgih condutivity (R ) The mixture of alumia and cryolite is used for electrolytic reduction ... (A) is incorrect but (R ) is correct

Description : Purity of oxygen used for blowing in steel making L.D. converter is 99.5%. The boiling point of oxygen is about __________ °C. (A) -53 (B) -103 (C) -183 (D) -196

Last Answer : (C) -183

Description : Electrolytic reduction of `Al_(2)O_(3)`. Electrolyte (`Al_(2)O_(3)+"cryolite")` Anode: Graphite rods. The purpose of adding crylite is :

Last Answer : Electrolytic reduction of `Al_(2)O_(3)`. Electrolyte (`Al_(2)O_(3)+"cryolite")` Anode: Graphite rods. ... . to increase melting point of `Al_(2)O_(3)`

Description : Mercury electrolytic cell produces 50-70% NaOH solution. Its operating temperature is __________ °C. (A) 25 (B) 60-70 (C) 150-200 (D) 250-300

Last Answer : (B) 60-70

Description : Fusion zone in the electric furnace used for reduction of phosphate rock to elemental phosphorous is maintained at __________ °C. (A) 250-300 (B) 500-750 (C) 950-1050 (D) 1400-1450

Last Answer : (D) 1400-1450

Description : Purity of electrical grade aluminium should be ≥ __________ percent. (A) 95 (B) 99.5 (C) 85 (D) 90

Last Answer : (B) 99.5

Description : Statement -I :Cryolite is used in electrolytic extraction of Al from alumuna.Statement -2: It dissilves alumina

Last Answer : Statement -I :Cryolite is used in electrolytic extraction of Al from alumuna. Statement -2: It dissilves alumina

Description : In a heat treatment shop, steel components are heat-treated in batches of 80 Tons. The  heat treatment cycle is as follows;  Increase temperature from 30 OC to 850 OC in 3 hours.  ... efficiency of 80%, for same requirement. The investment towards installation of  the new furnace is Rs. 50

Last Answer : Quantity of steel treated per batch - 80 Tons a. Efficiency of Furnace: Useful heat supplied to steel - 80000 x 0.12 x (850 - 30)   = 7872000 kcal/batch .1 mark Total heat ... = Rs. 64400/batch Efficiency of new LPG furnace - 80% Heat supplied in new LPG furnace - 7872000/0.8

Description : Electrolytic reduction of alumina to aluminum by the Hall-Heroult process is carried out

Last Answer : Electrolytic reduction of alumina to aluminum by the Hall-Heroult process is carried out A. In ... which forms a melt with higher melting temparature.

Description : The function of adding cryolite in the electrolytic reduction of alumina by Hall-Heroult process is to

Last Answer : The function of adding cryolite in the electrolytic reduction of alumina by Hall-Heroult ... D. increase the electrical canductivity of alumina

Description : During electrolytic reduction of alumina , two auxiliary electrolytes X and Y are added to increase the electrical conductance and lower the temperatu

Last Answer : During electrolytic reduction of alumina , two auxiliary electrolytes X and Y are added to increase ... . alum and flourspar D. flourspar and bauxite

Description : Describe electrolytic reduction of alumina.

Last Answer : i) Aluminium is extracted from alumina by electrolysis of mixture of alumina (20%) , Cryolite (60%) & Calcium fluoride (20%). Addition of cryolite& fluorspar not only makes alumina a ... set free at the cathode is removed periodically in the molten condition from bottom of the cell.

Description : In the manufacture of H3 PO4 (ortho); strong H2 SO4 leaching wet process as compared to electric furnace process (A) Uses lower grade phosphate rock (B) Requires lower capital investment in the plant (C) Produces lower purity acid (D) Is very costly

Last Answer : (C) Produces lower purity acid

Description : Which of the following is the most adverse factor challenging the choice of mercury electrolytic cell process for the production of caustic soda? (A) High cost of mercury (B) High specific gravity of mercury (C) Non-availability of high purity mercury (D) Pollution of water stream by mercury

Last Answer : (D) Pollution of water stream by mercury

Description : Mercury electrolytic cells are preferred over diaphragm electrolytic cell (for production of caustic soda), as it (A) Has larger production capacity per unit cell (B) Consumes less power per ton of Cl2 produced (C) Produces high purity (70%) caustic soda directly (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : Electrolytic reduction of `Al_(2)O_(3)`. Electrolyte (`Al_(2)O_(3)+"cryolite")` Anode: Graphite rods. Coke powder is spreadded over the molten electro

Last Answer : Electrolytic reduction of `Al_(2)O_(3)`. Electrolyte (`Al_(2)O_(3)+"cryolite")` Anode: Graphite rods. ... of molten aluminium by air D. (a) both (b)

Description : Electrolytic reduction of `Al_(2)O_(3)`. Electrolyte (`Al_(2)O_(3)+"cryolite")` Anode: Graphite rods. What is wrong if anode is made of nickel instant

Last Answer : Electrolytic reduction of `Al_(2)O_(3)`. Electrolyte (`Al_(2)O_(3)+"cryolite")` Anode: Graphite ... CO D. Nickel May be affected by high temperature.

Description : The major role of fluorpar (`CaF_2` ) which added in small quantities in the electrolyte reduction of alumina dissolved in fused cryolite `(N_(3)AlF_(

Last Answer : The major role of fluorpar (`CaF_2` ) which added in small quantities in the electrolyte reduction ... the rate of oxidation of carbon at the anode

Description : Rotary kilns in cement industry are lined with _________bricks. (A) Fireclay (B) Silica (C) Lead (D) High alumina & high magnesia

Last Answer : (D) High alumina & high magnesia

Description : Define the following : Electrochemistry , Electrolyte , Non-Electrolyte , Electrolytic Cell , Galvanic or Voltaic cell , Electrolysis , Hydrolysis & electroplating.

Last Answer : Ans : (a) Electrochemistry : Electrochemistry is the branch of chemistry which deals with such chemical reactions involving the inter-conversion of electrical energy and chemical energy. Example : Batteries , ... should be a solution of the coating metal, such as its metal nitrate or sulfate.

Description : Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3 /min) of density 800 kg/m3 and specific heat of ... mean temperature difference in °C is approximately (A) 32 (B) 37 (C) 45 (D) 50

Last Answer : (A) 32

Description : Electrolytic reducation of `Al_(2)O_(3)` Electrolyte `(Al_(2)O_(3)+cryolite) ` Cathode : fraphite inside Fe -Container The purpose of adding cryolite

Last Answer : Electrolytic reducation of `Al_(2)O_(3)` Electrolyte `(Al_(2)O_(3)+cryolite) ` Cathode : fraphite inside ... the impurities as slag D. Both (a) & (B)

Description : The sun is made up of 99.9% of -------- and -------? A. Oxygen and Hydrogen B. Hydrogen and Sulfur C. Carbon and Silicon D. Hydrogen and Helium (Answer)

Last Answer : D. Hydrogen and Helium (Answer)

Description : Operating condition in the electrical dehydrators for crude oil is about (A) 6.5 kgf/Cm2 & 95°C (B) 1 atm. & 110 °C (C) 20 kgf/cm2 & 110°C (D) 50 atm. and 150°C

Last Answer : (A) 6.5 kgf/Cm2 & 95°C

Description : Dust collection efficiency of electrostatic precipitator can be as high as 99.9%. Maximum temperature and pressure of dust laden gas that can be cleaned in an electrostatic precipitator is respectively. (A) 200°C and 5 atm (B) 1000°C and 10 atm (C) 500°C and 50 atm (D) 1000°C and 500 atm

Last Answer : (B) 1000°C and 10 atm

Description : The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2 /m3 ) (A) 500 (B) 1200 (C) 900 (D) 800

Last Answer : (A) 500

Description : At what temperature is glass fused to steel in the making of glass-lined equipment? The borosilicate glass is typically fused to carbon steel at a temperature of about 800 0C. 87. What are some typical applications for glass-lined reactors?

Last Answer : Glass-lined equipment gives superior protection to all mineral acids at all concentration and temperatures. One exception is hydrofluoric acid. They are also used is high-purity processes where cleanliness ... to the walls of the vessels while glass-lined vessels have good anti-stick properties.

Description : Coke is made by heating coal in the absence of air at: A. 700 °C B. 1300 °C C. 900 °C D. 1700 °C ANSWER: Why are soft drinks made with chilled water rather than water at room ... B. Chilled water enhances the taste C. Chilled water attracts more carbon dioxide D. Chilled water is more hygienic

Last Answer : ANSWER: C

Description : Although thermodynamically feasible, in practice, Magnesium metal is not used for the reduction of Alumina in the metallurgy of aluminium.Why?

Last Answer : Ans. : Below the temperature(1623 K) correspoinding to the point of intersection of Al 2O3 and MgO curves in Ellingham diagram, Magnesium can reduce Alumina because the ΔfG o value of Al2O3 at ... to Al. But Magnesium is much costier metal than Aluminium and hence the process will be uneconomical.

Description : Utilizing the answer to the previous problem, estimate the overall or average increase in temperature ( ΔT) of the concrete roof from the energy absorbed from the sun during a12hour day. Assume that all of the radiation absorbed goes into ... °C  b. 8.9°C  c. 9.9°C  d. 10.9°C formula: ΔQ = m c ΔT

Last Answer : 7.9 °C

Description : The refractory lining of the bottom in a basic electric arc furnace is made of (A) Silica (B) Alumina (C) Magnesia (D) Fireclay

Last Answer : Option C

Description : Liquid ammonia is shipped in __________ containers. (A) Steel (B) Aluminium (C) Glass (D) Lead lined

Last Answer : (C) Glass

Description : High speed steel tools retain their hardness upto a temperature of __________ °C. (A) 500 (B) 750 (C) 900 (D) 1100

Last Answer : (C) 900

Description : Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are ... __________ °C. (A) 400-500 (B) 900-1000 (C) 1400-1500 (D) 1700-1800

Last Answer : (B) 900-1000

Description : High speed steel tools retain their hardness upto a temperature of __________ °C. (A) 500 (B) 750 (C) 900 (D) 1100

Last Answer : Option C

Description : Nitriding of steel is done (in electric furnace) at __________ °C. (A) 510 (B) 1720 (C) 2210 (D) 910

Last Answer : (A) 510

Description : While the fuel fired furnace can be used upto a maximum temperature of about 1700°C, the electric furnace can be used upto a temperature of about __________ °C. (A) 2000 (B) 3000 (C) 4500 (D) 6000

Last Answer : (C) 4500

Description : In the illustration, the component labeled 'G' _________. EL-0031 A. is lined with cardboard to maintain a moisture (electrolyte) barrier between cells B. is a one piece container with compartments for each individual cell C. must be UL approved for shipboard use D. can only contain one cell

Last Answer : Answer: B

Description : For the metallurgical process of which of the ores calcined ore can be reduced by carbon?

Last Answer : For the metallurgical process of which of the ores calcined ore can be reduced by carbon? A. haematite B. Calamine C. Iron pyrites D. Sphalerite

Description : One face of a furnace wall is at 1030°C and the other face is exposed to room temperature (30°C). If the thermal conductivity of furnace wall is 3 W. m-1. k-1 and the wall thickness is 0.3 m, the maximum heat loss (in W/m) is (A) 100 (B) 900 (C) 9000 (D) 10000

Last Answer : (D) 10000

Description : . The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C-1 respectively. The ambient air is at 30°C ... from the outer surface in W.m-2 is (A) 165.4 (B) 167.5 (C) 172.5 (D) 175

Last Answer : (A) 165.4

Description : 99.5% purity oxygen is used in (A) Cutting and welding by oxy-acetylene flame (B) Hospitals for medicinal purposes (C) Gas masks and artificial breathing apparatus (D) All (A), (B), and (C)

Last Answer : (D) All (A), (B), and (C)

Description : Low temperature carbonisation of coal takes place at __________ °C. (A) 300 (B) 1100 (C) 700 (D) 900

Last Answer : (C) 700

Description : Transformer cores are normally made from (A) Soft ferrites (B) High purity iron (C) Grain oriented Fe-Si alloy (D) Al-Ni-Co alloy

Last Answer : (C) Grain oriented Fe-Si alloy

Description : Advantages of fluidised bed combustion are (A) Reduced NOx formation in flue gas (B) Lower furnace operating temperature (C) High heat transfer rate (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Description : If the expected time for completion of a project is 10 days with a standard deviation of 2 days, the expected time of completion of the project with 99.9% probability is (A) 4 days (B) 6 days (C) 10 days (D) 16 day

Last Answer : (D) 16 days

Description : Chlorine gas is produced by the electrolysis of brine (NaCl solution with solid NaCl make up) in mercury electrolytic cell. Which of the following is the anodic reaction? (A) Oxidation of Na + ions (B) Oxidation of Cl - ions (C) Reduction of Na + ions (D) Reduction of Cl - ions

Last Answer : (B) Oxidation of Cl - ions