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CBSE Class 12 (Science) General Principles and Processes of Isolation of Elements — practice questions
55 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 12 (Science) General Principles and Processes of Isolation of Elements in the app →Which concentration method uses air bubbles to lift water-repelling mineral grains?Roasting of an ore is carried out by heating it in a current of which gas mixture?Roasting a sulfide ore releases its sulfur mainly as which gas?Roasting zinc blende, ZnS, in air leaves which solid product?Smelting extracts a metal by applying heat together with what?Which product does a blast furnace give from iron ore before it is made into steel?Which flux is charged with coke and ore at the top of an iron blast furnace?What are the pipes that blow hot air into the lower blast furnace called?In an iron blast furnace, silica impurity combines with CaO to form what?Blast furnace pig iron holds roughly what percentage of carbon?In the Hall–Héroult process, alumina is dissolved in which molten compound?What is the formula of synthetic cryolite used in aluminium smelting?The Hall–Héroult electrolysis of alumina is run near which temperature?What is the approximate melting point of pure alumina?Why is alumina dissolved in molten cryolite before electrolysis?In the aluminium cell, liquid metal is deposited on which electrode?The aluminium electrolysis cell passes a heavy direct current at what voltage?Bauxite typically holds what range of aluminium oxide content?In the Bayer process, bauxite is digested under pressure with hot what?Digesting bauxite in caustic soda gives which soluble aluminium compound?What is the caustic waste left after digesting bauxite with NaOH?Sodium aluminate liquor is seeded with crystals of which compound to precipitate product?Strongly heating aluminium hydroxide in rotary kilns produces which substance?The Mond process purifies which metal through a volatile carbonyl?At what temperature does impure nickel react with CO to form the gaseous carbonyl?Which formula is the volatile nickel carbonyl of the Mond process?Heating impure titanium with iodine in a vacuum, then depositing pure metal on a hot wire, is which method?In the van Arkel process, metal iodide decomposes on a hot filament of which metal?In the Kroll process, which metal reduces titanium tetrachloride?An Ellingham plot shows how which quantity changes with temperature?On an Ellingham plot, a metal whose line lies lower forms an oxide that is what?Metal oxide formation lines on an Ellingham plot slope in which way?The line for C forming CO has what slope on an Ellingham plot?The C to CO2 line is almost flat because moles of gas in the reaction do what?Near which temperature do the CO and CO2 lines cross on an Ellingham plot?Thermite welding relies on aluminium reducing which oxide?In the 600 to 700 °C zone of a blast furnace, which is the stronger reductant?Ellingham plots help metallurgists chiefly to choose the best what?At the point where two Ellingham lines intersect, what is the reaction free energy change?Which oxides are so unstable that heat alone decomposes them?Which substance serves as a frother in flotation?Which salts are popular collectors for sulfide minerals in flotation?A reagent that stops one mineral reacting with the collector is called a what?Re-floating the tailings to recover leftover valuable grains is called what?Grinding ore into fine particles before flotation is termed what?Extracting metals using aqueous solutions, beginning with leaching, is called what?Dissolving valuable metals from an ore into a solution is known as what?Blister copper gets its name from the escape of which gas as it cools?In electrolytic refining of copper, selenium and tellurium settle as what?In copper matte smelting, which molten layer floats on top?Which substance is added to copper matte smelting to form a separate iron slag?Materials added in smelting to bind unwanted impurities are called what?Which roasting type heats ore in excess air and is the most common?Magnetic roasting turns non-magnetic Fe2O3 into which magnetic oxide?Roasting a sulfide ore until nearly all sulfur is removed gives which result?