CBSE Questions for Class 12 Engineering Chemistry General Principles And Processes Of Isolation Of Elements Quiz 2 - MCQExams.com

Which of the following is not a method of extraction of metals?
  • Enrichment of ore
  • Refining
  • Magnetic separation
  • None of the above
Which of the following technique uses high temperature to convert ore into raw metals?
  • Pyrometallurgy
  • Hydrometallurgy
  • Both a and b
  • None of above
Which of the following is a physical mean for concentration of ore?
  • Using sodium hydroxide
  • Using electrolysis
  • Froth flotation method
  • None of above
What is the most common type of electrometallurgical processes to obtain pure metal?
  • Electro-refining
  • Electrowinning
  • Both a and b
  • Oxidation
Aluminium foils are used for:
  • wrapping chocolates and food stuff
  • to prepare hydrogen
  • both $$A$$ and $$B$$
  • none of these
Which of the following pairs is incorrect?
  • Gneiss - Metamorphic
  • Rock salt - Sedimentary
  • Dolerite - Igneous
  • Dolomite - Igneous
When $$ZnS$$ and $$PbS$$ minerals are present together, then $$NaCN$$ is added to separate them in the froth flotation process as a depressant, because:
  • $$Pb(CN)_2$$ precipitated while no effect on $$ZnS$$
  • $$ZnS$$ forms soluble complex $$Na_2 Zn(CN)_4$$
  • $$PbS$$ forms soluble complex $$Na_2Pb(CN)_4$$
  • both $$(a)$$ and $$(b)$$
______ metal generally occurs in free state.
  • Sodium
  • Platinum
  • Magnesium
  • Potassium
The earthy impurities present in the mineral are called:
  • flux
  • slag
  • gangue
  • refractory material
The final product in solvay process is:
  • $$Na_{2}CO_{3}$$
  • $$Na_{2}CO_{3}.10H_{2}O$$
  • $$Na_{2}CO_{3}.H_{2}O$$
  • $$Na_{2}CO_{3}.8H_{2}O$$
Method used for the concentration of sulphide ore is :
  • hand picking
  • froth floatation
  • magnetic separation
  • leaching
The olive oil used in froth floatation process is called :
  • frothing agent
  • collecting agent
  • conditioning agent
  • lubricating agent
The extraction of metal from the ore is:
  • an oxidation process
  • a reduction process
  • a hydration process
  • a neutralisation process
Match Column 1 with Column 2:

Column 1 
Column 2
A. Mond's process$$1.\ Cr_{2}O_{3}+2Al\xrightarrow{\triangle}2Cr+Al_{2}O_{3}$$ 
B. van Arkel process 
$$2.\ TiCl_{4}+2Mg \xrightarrow{\triangle}Ti+2MgCl_{2}$$
C. Thermite process$$3.\ Ni(CO)_{4} \xrightarrow{\triangle}Ni+4CO$$
D. Kroll's process$$4.\ ZrI_{4} \xrightarrow{\triangle}Zr+2I_{2}$$
  • A - 1; B - 2; C - 3; D - 4
  • A - 2; B - 4; C - 3; D - 1
  • A - 3; B - 2; C - 1; D - 4
  • A - 3; B - 4; C - 1; D - 2
Generally sulphide ores are concentrated by which of the following process?
  • Hand picking
  • Washing with water
  • Leaching
  • Froth floatation
The collecting agent in froth floatation process is:
  • sodium ethyl xanthate
  • pine oil
  • lime
  • water
Liquation process is used for the concentration of which ore?
  • Stibinite
  • Tinstone
  • Limestone
  • Haematite
Natron is a mineral whose formula represented by:
  • $$Na_{2}CO_{3}.H_{2}O$$
  • $$Na_{2}CO_{3}.10H_{2}O$$
  • $$Na_{2}SO_{4}.H_{2}O$$
  • $$Na_{2}SO_{4}.7H_{2}O$$
100% copper is obtained from crude copper by :
  • zone refining method
  • electrorefining
  • liquation
  • poling
Liquation method is used to refine which of the following crude metal?
  • Silver
  • Lead
  • Mercury
  • Copper
Which one of the following is used in the extraction of aluminium by electrolytic process?
  • $$Al_{2}O_{3}$$
  • $$Al(OH)_{3}$$
  • $$AlCl_{3}$$
  • $$Al_{2}(SO_{4})_{3}$$
Aluminium is obtained by the electrolysis of pure $$Al_{2}O_{3}$$, dissolved in:
  • alumina
  • bauxite
  • cryolite and flourspar 
  • feldspar
Which of the following metal is refined by distillation method?
  • Zinc
  • Iron
  • Tin
  • Copper
Zone refining method is used for refining:
  • $$Al$$
  • $$Ge$$
  • $$Cu$$
  • $$Fe$$
In the extraction of aluminium the electrolyte is:
  • fused cryolite with felspar
  • fused cryolite with fluorspar
  • pure alumina in molten cryolite with fluorospar
  • pure alumina with bauxite and molten cryolite
In the extraction of aluminium by electrolytic process, cryolite is added to ________.
  • lower the melting point of alumina
  • increase the electrical conductivity
  • minimise the anode effect
  • remove impurities from alumina
Carbon cannot be used to reduce :
  • $$ZnO$$
  • $$SnO_{2}$$
  • $$Fe_{2}O_{3}$$
  • $$Al_{2}O_{3}$$
Which of the following technique is used in the manufacture of aluminium from bauxite?
  • Reduction with magnesium
  • Reduction with coke
  • Electrolytic reduction
  • Reduction with iron
The formula of the most abundant salt of sodium in nature is:
  • $$NaNO_{3}$$
  • $$NaCl$$
  • $$Na_{2}CO_{3}$$
  • $$Na_{2}SO_{4}$$
In the Castner's process of extraction of sodium, the cathode is:
  • iron rod
  • nickel rod
  • copper rod
  • graphite rod
The metal obtained in the Pidgeon process is:
  • $$Na$$
  • $$Mg$$
  • $$Ca$$
  • $$Al$$
The solubility of impurities in a metal in molten and solid states is different. This is principle involved in the refining of a metal by which of the following methods?
  • Poling
  • Liquation
  • Zone refining
  • Electrolysis
Identify the reaction during electrolytic reduction of alumina at cathode.
  • $$2H_{2}O_{2}\rightarrow O_{2}+4H^{+}+4e^{-}$$
  • $$3F^{-}\rightarrow 3F+3e^{-}$$
  • $$Al^{+3}+3e^{-}\rightarrow Al$$
  • $$2H^{+}+2e^{-}\rightarrow H_{2}$$
Cryolite is used in the electrolytic extraction of aluminium, because ___________ .
  • it dissolves alumina
  • it dissolves sodium
  • it dissolves aluminium fluoride
  • it decreases the solubility
In the Castner process for the extraction of sodium, the anode is made of:
  • copper
  • iron
  • sodium
  • nickel
The froth floatation process is used for the concentration of:
  • ore having low density
  • ore having magnetic nature
  • ore having high density
  • ore having water soluble gangue
Chile salt petre is the nitrate mineral of :
  • potassium
  • sodium
  • calcium
  • lithium
The cathode used in the electrolytic cell during aluminium extraction is made of ____________.
  • aluminium
  • carbon Iining
  • iron
  • steel
ASSERTION: In froth floatation process, sodium ethyl xanthate is used as a collector.
REASON: Sulphide ores are water soluble.
  • If both assertion and reason are CORRECT, and the reason is the CORRECT explanation of the assertion.
  • If both assertion and reason are CORRECT, but the reason is NOT the CORRECT explanation of the assertion.
  • If assertion is CORRECT but reason is INCORRECT.
  • If assertion is INCORRECT but reason is CORRECT.
Ellingham diagram represents the change in:
  • $$ G$$ with temperature
  • $$ H$$ with temperature
  • $$ G$$ with pressure
  • $$G-T S$$ with temperature
Which one of the following ores is best concentrated by froth-floatation method? 
  • Magnetite
  • Cassiterite
  • Galena
  • Malachite
The method of zone refining of metals is based on the principle of:
  • greater mobility of the pure metal than that of impurity
  • higher melting point of the impurity than that of the pure metal
  • greater noble character of the solid metal than that of the impurity
  • greater solubility of the impurity in the molten state than in the solid state
Molecular formula of Glauber salt is:
  • $$CuSO_{4}.5H_{2}O$$
  • $$MgSO_{4}.7H_{2}O$$
  • $$Na_{2}SO_{4}.10H_{2}O$$
  • $$FeSO_{4}.7H_{2}O$$
Froth floatation process for the concentration of sulphide ores is an illustration of the practical application of:
  • adsorption
  • absorption
  • sedimentation
  • coagulation
ASSERTION: $$CuFeS_{2}$$ is concentrated by froth floatation method.
REASON: $$CuFeS_{2}$$ is the main ore of copper.
  • If both assertion and reason are CORRECT, and reason is the CORRECT explanation of the assertion
  • If both assertion and reason are CORRECT, but reason is NOT the CORRECT explanation of the assertion
  • If assertion is CORRECT but reason is INCORRECT
  • If assertion is INCORRECT but reason is CORRECT
Which is not a mineral of aluminium?
  • Anhydrite
  • Bauxite
  • Corundum
  • Diaspore

The common metal present in german silver, bell metal and brass is :
  • Fe
  • Cu
  • Zn
  • Sn
Which one of the following statements is incorrect?
  • In the aluminothermite process, aluminium acts as reducing agent.
  • Lead is extracted from its chief ore by both carbon reduction and self-reduction.
  • Zinc is extracted from its chief ore by carbon reduction.
  • Extraction of gold involves the leaching of ore with cyanide solution followed by reduction with zinc.
  • In Hall-Heroult process, the electrolyte used is a molten mixture of alumina, sodium hydroxide and cryolite.
Given below are the steps for extraction of copper from its ore. The balance reaction involved in reduction of copper(I) oxide with copper(I) sulphide is given in the reaction below.

      $$2Cu_{2}O + Cu_{2}S \xrightarrow{Heat} 6Cu + SO_{2}$$. 

This reaction is known as:
  • auto-reduction
  • catalytic- reduction
  • acid reduction
  • none of these
Which of the following reactions does not occur in Bessemer's converter?
  • $$2Cu_{2}S+5O_{2}\rightarrow 2CuSO_{4}+2CuO$$
  • $$2Cu_{2}S+3O_{2}\rightarrow 2Cu_{2}O+2SO_{2}\uparrow $$
  • $$2CuFeS_{2}+O_{2}\rightarrow Cu_{2}S+2FeS+SO$$
  • $$FeO+SiO_2\rightarrow FeSiO_3$$
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