NEET Chemistry Metallurgy / धातुकर्म Question Bank

done Self Evaluation Test - General Principals and Process of Isolation of Elements Total Questions - 70

• question_answer1)
  Which one of the following is not a sulphide ore?
  A)
  Magnetite done clear
  B)
  Iron pyrites done clear
  C)
  Copper glance    done clear
  D)
  Sphalerite done clear
  View Solution play_arrow

• question_answer2)
  Which of the following pair is incorrectly matched?
  A)
  Magnetite - \[F{{e}_{3}}{{O}_{4}}\] done clear
  B)
  Copper glance - \[C{{u}_{2}}S\] done clear
  C)
  Calamine-\[ZnC{{O}_{3}}\] done clear
  D)
  Zincite - \[ZnS\] done clear
  View Solution play_arrow

• question_answer3)
  The impurities associated with mineral used in metallurgy are called collectively?
  A)
  Slag                  done clear
  B)
  Flux  done clear
  C)
  Gangue             done clear
  D)
  Ore done clear
  View Solution play_arrow

• question_answer4)
  Galena is an ore of
  A)
  Pb                                done clear
  B)
  Hg   done clear
  C)
  Zn                                 done clear
  D)
  Cu done clear
  View Solution play_arrow

• question_answer5)
  The process of converting hydrated alumina into anhydrous alumina is called
  A)
  roasting             done clear
  B)
  smelting done clear
  C)
  dressing             done clear
  D)
  calcination done clear
  View Solution play_arrow

• question_answer6)
  Which of the following statements regarding metallurgy of iron is incorrect?
  A)
  Reaction \[F{{e}_{3}}{{O}_{4}}+4CO\xrightarrow{{}}3Fe+4C{{O}_{2}}\] belongs to lower temperature range (500 - 800K) of the blast furnace. done clear
  B)
  Reaction \[FeO+CO\xrightarrow{{}}Fe+C{{O}_{2}}\] belongs to higher temperature range (900 -1500K) of the blast furnace. done clear
  C)
  The iron obtained from blast furnace is cast iron with 3% carbon. done clear
  D)
  For reduction of iron oxide to occur \[\Delta G\] of the couple of following reactions should be negative           \[FeO(s)\xrightarrow{{}}Fe(s)+\frac{1}{2}{{O}_{2}}(g)\] \[C(s)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}CO(g)\] done clear
  View Solution play_arrow

• question_answer7)
  The most electropositive metals are isolated from their ores by
  A)
  high temperature reduction with carbon done clear
  B)
  self reduction done clear
  C)
  thermal decomposition done clear
  D)
  electrolysis of fused ionic salts done clear
  View Solution play_arrow

• question_answer8)
  Which of the following condition favours the reduction of a metal oxide to metal?
  A)
  \[\Delta H=+ve,T\Delta S=+ve\] at low temperature done clear
  B)
  \[\Delta H=+ve,T\Delta S=-ve\] at any temperature done clear
  C)
  \[\Delta H=-ve,T\Delta S=-ve\] at high temperature done clear
  D)
  \[\Delta H=-ve,T\Delta S=+ve\] at any temperature done clear
  View Solution play_arrow

• question_answer9)
  Which of the following statements regarding electrolytic refining of copper is incorrect?
  A)
  In this process anode is made up of impure copper and pure copper strips are taken as cathode. done clear
  B)
  Acidic or basic solution of copper sulphate is used as electrolyte done clear
  C)
  Antimony, tellurium, silver and gold are some of the metals deposits as anode mud during this process done clear
  D)
  Zinc can be also refined by electrolytic refining method. done clear
  View Solution play_arrow

• question_answer10)
  If an impurity in a metal has a greater affinity for oxygen and is more easily oxidised than the metal, then the purification of metal may be carried out by
  A)
  Poling                done clear
  B)
  Zone refining done clear
  C)
  Electrolytic refining done clear
  D)
  Cupellation done clear
  View Solution play_arrow

• question_answer11)
  van Arkel method of purification of metals involves converting the metal to a
  A)
  volatile stable compound done clear
  B)
  volatile unstable compound done clear
  C)
  non volatile stable compound done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer12)
  In order to refine "blister copper" it is melted in a furnace and is stirred with green logs of wood. The purpose is
  A)
  to expel the dissolved gases in blister copper. done clear
  B)
  to bring the impurities to surface and oxidize them. done clear
  C)
  to increase the carbon content of copper. done clear
  D)
  to reduce the metallic oxide impurities with hydrocarbon gases liberated from the wood. done clear
  View Solution play_arrow

• question_answer13)
  The value of \[{{\Delta }_{f}}G{}^\circ \] for formation of \[C{{r}_{2}}{{O}_{3}}\] is \[-540\text{ }kJmo{{l}^{-1}}\]  and that of \[A{{l}_{2}}{{O}_{3}}\] is \[-827\text{ }kJ\text{ }mo{{l}^{-1}}\]  What is the value of \[{{\Delta }_{f}}G{}^\circ \] for the reaction? \[\frac{4}{3}Al(s)+\frac{2}{3}C{{r}_{2}}{{O}_{3}}(s)\to \frac{2}{3}A{{l}_{2}}{{O}_{3}}(s)+\frac{4}{3}Cr(s).\]
  A)
  \[-574\text{ }kJ\,mo{{l}^{-1}}\]            done clear
  B)
  \[-287\,kJ\,mo{{l}^{-1}}\] done clear
  C)
  \[+574\text{ }kJ\,mo{{l}^{-1}}\]    done clear
  D)
  \[+287kJ\,mo{{l}^{-1}}\] done clear
  View Solution play_arrow

• question_answer14)
  Which of the following statement is not correct about Ellingham diagram?
  A)
  \[\Delta G\] increases with an increase in temperature done clear
  B)
  It consists of plots of \[{{\Delta }_{f}}G{}^\circ \] Vs T for formation of oxides done clear
  C)
  A coupling reaction can be well expressed by this diagram done clear
  D)
  It express the kinetics of the reduction process done clear
  View Solution play_arrow

• question_answer15)
  Iron is obtained on large scale from \[F{{e}_{2}}{{O}_{3}}\] by
  A)
  Reduction with CO done clear
  B)
  Reduction with Al done clear
  C)
  Calcination       done clear
  D)
  Passing \[{{H}_{2}}\] done clear
  View Solution play_arrow

• question_answer16)
  Aluminothermic process is used for the extraction of metals, whose oxides are
  A)
  fusible done clear
  B)
  not easily reduced by carbon done clear
  C)
  not easily reduced by hydrogen done clear
  D)
  strongly basic. done clear
  View Solution play_arrow

• question_answer17)
  When \[CuS{{O}_{4}}\] is electrolysed using platinum electrodes,
  A)
  copper is liberated at cathode, sulphur at  anode done clear
  B)
  copper is liberated at cathode, oxygen at anode done clear
  C)
  sulphur is liberated at cathode; oxygen anode done clear
  D)
  oxygen is liberated at cathode, copper at anode done clear
  View Solution play_arrow

• question_answer18)
  Which one of the following is a mineral of iron?
  A)
  Malachite           done clear
  B)
  Cassiterite done clear
  C)
  Pyrolusite           done clear
  D)
  Magnetite done clear
  View Solution play_arrow

• question_answer19)
  In the extraction of copper from its sulphide ore, the metal finally obtained by the reduction of cuprous oxide with
  A)
  iron (II) sulphide done clear
  B)
  carbon monoxide done clear
  C)
  copper (I) sulphide done clear
  D)
  sulphur dioxide done clear
  View Solution play_arrow

• question_answer20)
  Calamine is an ore of:
  A)
  zinc                               done clear
  B)
  aluminium done clear
  C)
  iron                               done clear
  D)
  copper done clear
  View Solution play_arrow

• question_answer21)
  Which one of the following ores is known as Malachite:
  A)
  \[C{{u}_{2}}O\]                        done clear
  B)
  \[C{{u}_{2}}S\] done clear
  C)
  \[CuFe{{S}_{2}}\]                     done clear
  D)
  \[Cu{{\left( OH \right)}_{2}}.CuC{{O}_{3}}\] done clear
  View Solution play_arrow

• question_answer22)
  In the isolation of metals, calcination process usually results in:
  A)
  metal hydroxide   done clear
  B)
  metal sulphide done clear
  C)
  metal oxide       done clear
  D)
  metal carbonate done clear
  View Solution play_arrow

• question_answer23)
  Cryolite is
  A)
  \[N{{a}_{3}}Al{{F}_{6}}\] and used in the electrolysis of alumina for decreasing electrical conductivity done clear
  B)
  \[N{{a}_{3}}Al{{F}_{6}}\]and used in the electrolysis of alumina for lowering the melting point of alumina done clear
  C)
  \[N{{a}_{3}}Al{{F}_{6}}\]and used in the electrolytic purification of alumina done clear
  D)
  \[N{{a}_{3}}Al{{F}_{6}}\] and used in the electrolysis of alumina done clear
  View Solution play_arrow

• question_answer24)
  Froth floatation process is used for the metallurgy of
  A)
  chloride ores       done clear
  B)
  amalgams done clear
  C)
  oxide ores          done clear
  D)
  sulphide ores done clear
  View Solution play_arrow

• question_answer25)
  Which of the following metal is leached by cyanide process
  A)
  Ag                                done clear
  B)
  Na done clear
  C)
  Al                                 done clear
  D)
  Cu done clear
  View Solution play_arrow

• question_answer26)
  Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?
  A)
  The \[\Delta G_{f}^{{}^\circ }\] of the sulphide is greater than those for \[C{{S}_{2}}\] and \[{{H}_{2}}s\]. done clear
  B)
  The \[\Delta G_{f}^{{}^\circ }\] is negative for roasting of sulphide ore to oxide. done clear
  C)
  Roasting of the sulphide to the oxide is thermodynamically feasible. done clear
  D)
  Carbon and hydrogen are suitable reducing agents for reduction of metal sulphides. done clear
  View Solution play_arrow

• question_answer27)
  Sulphide ores of metals are usually concentrated by froth flotation process. Which one of the following sulphide ores offer an exception and is concentrated by chemical leaching?
  A)
  Galena              done clear
  B)
  Copper pyrite done clear
  C)
  Sphalerite          done clear
  D)
  Argentite done clear
  View Solution play_arrow

• question_answer28)
  Pb and Sn are extracted from their chief ore by
  A)
  carbon reduction and self reduction. done clear
  B)
  self reduction and carbon reduction. done clear
  C)
  electrolysis and self reduction. done clear
  D)
  self-reduction and electrolysis. done clear
  View Solution play_arrow

• question_answer29)
  Which of the following elements is present as the impurity to the maximum extent in the pig iron?
  A)
  Manganese         done clear
  B)
  Carbon done clear
  C)
  Silicon                           done clear
  D)
  Phosphorus done clear
  View Solution play_arrow

• question_answer30)
  Which of the following pairs of metals is purified by van Arkel method?
  A)
  Ga and in          done clear
  B)
  Zr and Ti done clear
  C)
  Ag and Au         done clear
  D)
  Ni and Fe done clear
  View Solution play_arrow

• question_answer31)
  The following reactions take place in the blast furnace in the preparation of impure iron. Identify the reaction pertaining to the formation of the slag
  A)
  \[F{{e}_{2}}{{O}_{3}}(s)+3CO(g)\to 2Fe(l)+3C{{O}_{2}}(g)\] done clear
  B)
  \[CaC{{O}_{3}}(s)\to CaO(s)+C{{O}_{2}}(g)\] done clear
  C)
  \[CaO\left( s \right)+Si{{O}_{2}}\left( s \right)\to CaSi{{O}_{3}}\left( s \right)\] done clear
  D)
  \[2C\left( s \right)+{{O}_{2}}\left( g \right)\to 2CO\left( g \right)\] done clear
  View Solution play_arrow

• question_answer32)
  Aluminium is extracted from alumina \[(A{{l}_{2}}{{O}_{3}})\] by electrolysis of a molten mixture of
  A)
  \[A{{l}_{2}}{{O}_{3}}+HF+NaAl{{F}_{4}}\] done clear
  B)
  \[A{{l}_{2}}{{O}_{3}}+Ca{{F}_{2}}+NaAl{{F}_{4}}\] done clear
  C)
  \[A{{l}_{2}}{{O}_{3}}+N{{a}_{3}}Al{{F}_{6}}+Ca{{F}_{2}}\] done clear
  D)
  \[A{{l}_{2}}{{O}_{3}}+KF+N{{a}_{3}}Al{{F}_{6}}\] done clear
  View Solution play_arrow

• question_answer33)
  Correct match is:
  A)
  Bayer's method               -   \[N{{a}_{2}}C{{O}_{3}}\] done clear
  B)
  Matte                              -   98% \[C{{u}_{2}}S+2\]% \[FeS\] done clear
  C)
  van Arkel method           -   AgI done clear
  D)
  Thomas slag                   -  Raw material for cement industry done clear
  View Solution play_arrow

• question_answer34)
  Consider the following metallurgical processes:

  (I) Heating impure metal CO and distilling the resulting volatile carbonyl \[\left( b.p.\text{ }43{}^\circ C \right)\] and finally decomposition at \[150{}^\circ -200{}^\circ C\] to get the pure metal

  (II) Heating the sulphide ore in air until a part is converted to oxide and then furher heating in the absence of air to let the oxide react with unchanged metal sulphide

  (III) Electrolysis of the molten electrolyte containing approximately equal amounts of the metal chloride and \[NaCl\] to obtained the metal

  The processes used for obtaning magnesium, nickel and copper are respectively:

  A)
  (I), (II) and (III)               done clear
  B)
  (II), (III) and (I) done clear
  C)
  (III), (I) and (II)               done clear
  D)
  (II), (I) and (III) done clear
  View Solution play_arrow

• question_answer35)
  When copper pyrites is roasted in excess of air, a mixture of \[CuO+FeO\] is formed. \[FeO\] is present as impurity. This can be removed as slag during reduction of \[FeO\]. The flux added to form slag is
  A)
  \[Si{{O}_{2}}\] which is an acidic flux done clear
  B)
  Limestone, which is a basic flux done clear
  C)
  \[Si{{O}_{2}}\] which is the basic flux done clear
  D)
  CaO, which is a basic flux done clear
  View Solution play_arrow

• question_answer36)
  One of the processes used for concentration of ores is Froth floatation process. This process is generally used for concentration of sulphide ores. Sometimes in this process we add NaCN as a depressant. NaCN is generally added in case of ZnS and PbS minerals. What is the purpose of addition of NaCN during the process of Froth floatation?
  A)
  NaCN causes reduction by precipitation done clear
  B)
  A soluble complex is formed by reaction between NaCN and ZnS while PbS forms froth done clear
  C)
  A soluble complex is formed by reaction between NaCN and PbS while ZnS forms froth done clear
  D)
  A precipitate of \[Pb{{(CN)}_{2}}\] is produced while ZnS remain unaffected. done clear
  View Solution play_arrow

• question_answer37)
  Which of the following statement(s) is/are correct?

  (i) Cast iron is used in the manufacture of railway sleepers

  (ii) Wrought iron is used in the manufacture of anchors, bolts, chains etc.

  (iii) Nickel steel is used in making pendulums.

  A)
  Only (i)              done clear
  B)
  (i) and (ii) done clear
  C)
  (i),(ii) and (iii)     done clear
  D)
  Only (iii) done clear
  View Solution play_arrow

• question_answer38)
  A coupled reaction takes place as follow-

  \[A+B\xrightarrow{{}}C+D\]     \[\Delta G{}^\circ =+xkj\]

  \[D+E\xrightarrow{{}}F\]            \[\Delta G{}^\circ =-ykj\]

  for the spontaneity of reaction

  \[A+B+E\xrightarrow{{}}C+F\], which of the following is correct?

  A)
  \[2x=y\]                        done clear
  B)
  \[x<y\] done clear
  C)
  \[x>y\]                          done clear
  D)
  \[x=\left( y \right)\times T\Delta S\] done clear
  View Solution play_arrow

• question_answer39)
  The form of iron obtained from blast furnace is:
  A)
  Steel                             done clear
  B)
  Cast Iron done clear
  C)
  Pig Iron             done clear
  D)
  Wrought Iron done clear
  View Solution play_arrow

• question_answer40)
  Calcination is the process in which:
  A)
  ore is heated above its melting point to expel \[{{H}_{2}}O\] or \[C{{O}_{2}}\] or \[S{{O}_{2}}\] done clear
  B)
  ore is heated below its melting point to expel volatile impurities done clear
  C)
  ore is heated above its melting point to remove S, As and Sb as \[S{{O}_{2}},\,\,A{{s}_{2}}{{O}_{3}}\] and \[S{{b}_{2}}{{O}_{3}}\] respectively done clear
  D)
  ore is heated below its melting point to expel \[{{H}_{2}}O\] or \[C{{O}_{2}}\] done clear
  View Solution play_arrow

• question_answer41)
  In Goldschmidt aluminothermic process which of the following reducing agents is used:
  A)
  calcium             done clear
  B)
  coke done clear
  C)
  Al-powder          done clear
  D)
  sodium done clear
  View Solution play_arrow

• question_answer42)
  Pyrolusite is a/an
  A)
  oxide ore           done clear
  B)
  sulphide ore done clear
  C)
  carbide ore         done clear
  D)
  Not an ore done clear
  View Solution play_arrow

• question_answer43)
  Among the following statements the incorrect one is
  A)
  Calamine and siderite are carbonates done clear
  B)
  Argentite and cuprite are oxides done clear
  C)
  Zinc blende and iron pyrites are sulphides done clear
  D)
  Malachite and azurite are ores of copper. done clear
  View Solution play_arrow

• question_answer44)
  During smelting an additional substance is added which combines with impurities to form a fusible product. It is known as
  A)
  slag                   done clear
  B)
  mud done clear
  C)
  gangue              done clear
  D)
  flux done clear
  View Solution play_arrow

• question_answer45)
  Which of the following processes involve the roasting process?
  A)
  \[ZnC{{O}_{3}}\to ZnO+C{{O}_{2}}\] done clear
  B)
  \[F{{e}_{2}}{{O}_{3}}+3C\to 2Fe+3CO\] done clear
  C)
  \[2PbS+3{{O}_{2}}\to 2PbO+2S{{O}_{2}}\] done clear
  D)
  \[A{{l}_{2}}{{O}_{3}}.2{{H}_{2}}O\to A{{l}_{2}}{{O}_{3}}+2{{H}_{2}}O\] done clear
  View Solution play_arrow

• question_answer46)
  Before introducing \[FeO\]in blast furnace , it is converted to \[F{{e}_{2}}{{O}_{3}}\] by roasting so that
  A)
  it may not be removed as slag with silica done clear
  B)
  it may not evaporate in the furnace done clear
  C)
  presence of it may increase the m.pt. of charge done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer47)
  In electrorefining of copper some gold is deposited as
  A)
  anode mud       done clear
  B)
  cathode mud done clear
  C)
  electrolyte          done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer48)
  In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with:
  A)
  Copper (I) sulphide \[(C{{u}_{2}}S)\] done clear
  B)
  Sulphur dioxide \[\left( S{{O}_{2}} \right)\] done clear
  C)
  Iron sulphide \[\left( FeS \right)\] done clear
  D)
  Carbon monoxide (CO) done clear
  View Solution play_arrow

• question_answer49)
  \[XC{{l}_{2}}(excess)+YC{{l}_{2}}\xrightarrow{{}}XC{{l}_{4}}+Y\downarrow ;\] \[YO\xrightarrow[>400{}^\circ ]{\Delta }\frac{1}{2}{{O}_{2}}+Y,\] Ore of Y would be:
  A)
  Siderite              done clear
  B)
  Cinnabar done clear
  C)
  Malachite       done clear
  D)
  Hornsilver done clear
  View Solution play_arrow

• question_answer50)
  Refractory materials are generally used in furnaces because
  A)
  they possess great structural strength done clear
  B)
  they can withstand high temperature done clear
  C)
  they are chemically inert done clear
  D)
  they do not require replacement done clear
  View Solution play_arrow

• question_answer51)
  In electro-refining of metal the impure metal is made the anode and a strip of pure metal, the cathode, during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of
  A)
  silver                             done clear
  B)
  copper done clear
  C)
  aluminium        done clear
  D)
  sodium done clear
  View Solution play_arrow

• question_answer52)
  When the sample of copper with zinc impurity is to be purified by electrolysis, the appropriate electrodes are
  A)

  Cathode	Anode
  Pure zinc	Pure copper

  done clear
  B)

  Cathode	Anode
  Impure sample	Pure copper

  done clear
  C)

  Cathode	Anode
  Impure sample	Impure sample

  done clear
  D)

  Cathode	Anode
  Pure copper	Impure sample

  done clear
  View Solution play_arrow

• question_answer53)
  In the extraction of aluminium by Hall-Heroult process, purified \[A{{l}_{2}}{{O}_{3}}\] is mixed with \[Ca{{F}_{2}}\] to

  (i) lower the melting point of \[A{{l}_{2}}{{O}_{3}}\].

  (ii) increase the conductivity of molten mixture.

  (iii) reduce \[A{{l}^{3+}}\] into \[Al\left( s \right).\]

  (iv) acts as catalyst.

  A)
  (i) and (ii)  done clear
  B)
  (i), (ii) and (iii) done clear
  C)
  (iii) and (iv)                    done clear
  D)
  (ii), (iii) and (iv) done clear
  View Solution play_arrow

• question_answer54)
  In Hall-Heroult process how much carbon anode is burnt away to produce each 1kg of aluminium?
  A)
  0.3kg                 done clear
  B)
  0.5kg done clear
  C)
  1kg                               done clear
  D)
  0.1kg done clear
  View Solution play_arrow

• question_answer55)
  Which of the oxide groups among the following cannot be reduced by carbon?
  A)
  \[C{{u}_{2}}O,Sn{{O}_{2}}\]              done clear
  B)
  \[CaO,{{K}_{2}}O\] done clear
  C)
  \[PbO,F{{e}_{2}}{{O}_{4}}\]               done clear
  D)
  \[F{{e}_{2}}{{O}_{3}},ZnO\] done clear
  View Solution play_arrow

• question_answer56)
  Extraction of zinc from zinc blende is achieved by
  A)
  roasting followed by self-reduction done clear
  B)
  electrolytic reduction done clear
  C)
  roasting followed by reduction with carbon done clear
  D)
  roasting followed by reduction with another metal done clear
  View Solution play_arrow

• question_answer57)
  The substance used as froth stabilisers in froth- floatation process is
  A)
  Potassium ethyl xanthate done clear
  B)
  Aniline done clear
  C)
  Sodium cyanide done clear
  D)
  Copper sulphate done clear
  View Solution play_arrow

• question_answer58)
  When a metal is to be extracted from its ore and the gangue associated with the ore is silica, then
  A)
  an acidic flux is needed done clear
  B)
  a basic flux is needed done clear
  C)
  both acidic and basic fluxes are needed done clear
  D)
  Neither of them is needed done clear
  View Solution play_arrow

• question_answer59)
  Which one of the following ores is not concentrated by froth floatation process?
  A)
  Copper pyrites   done clear
  B)
  Pyrargyrite done clear
  C)
  Pyrolusite        done clear
  D)
  Zinc blende done clear
  View Solution play_arrow

• question_answer60)
  Which of the following reactions is an example for calcination process?
  A)
  \[2Ag+2HCl+(O)\to 2AgCl+{{H}_{2}}O\] done clear
  B)
  \[2Zn+{{O}_{2}}\to 2ZnO\] done clear
  C)
  \[2ZnS+3{{O}_{2}}\to 2ZnO+2S{{O}_{2}}\] done clear
  D)
  \[MgC{{O}_{3}}\to MgO+C{{O}_{2}}\] done clear
  View Solution play_arrow

• question_answer61)
  Heating of ore in the absence of air below its melting point is called
  A)
  leaching             done clear
  B)
  roasting done clear
  C)
  smelting             done clear
  D)
  calcination done clear
  View Solution play_arrow

• question_answer62)
  Heating pyrites to remove sulphur is called
  A)
  smelting             done clear
  B)
  calcination done clear
  C)
  liquation            done clear
  D)
  roasting done clear
  View Solution play_arrow

• question_answer63)
  Complexes formed in the following methods are

  I.	Mond's process for purification of nickel.
  II.	Removal of lead poisoning from the body.
  III.	Cyanide process for extraction of silver.
  IV.	Froth flotation process for separation of ZnS from galena ore by using depressant.

  A)

  	I.	II.	III.	IV.
  	\[Ni{{\left( CO \right)}_{4}}\]	\[[Pb{{\left( EDTA \right]}^{2-}}\]	\[{{[Ag{{\left( CN \right)}_{2}}]}^{-}}\]	\[[Zn{{(CN)}_{2}}]\]

  done clear
  B)

  	I.	II.	III.	IV.
  	\[Ni{{\left( CO \right)}_{4}}\]	\[[Pb{{\left( EDTA \right]}^{2-}}\]	\[{{[Ag{{\left( CN \right)}_{2}}]}^{-}}\]	\[{{[Zn{{(CN)}_{4}}]}^{2-}}\]

  done clear
  C)

  	I.	II.	III.	IV.
  	\[Ni{{\left( CO \right)}_{6}}\]	\[[Pb{{\left( EDTA \right]}^{4-}}\]	\[{{[Ag{{\left( CN \right)}_{2}}]}^{-}}\]	\[{{[Zn{{(CN)}_{6}}]}^{4-}}\]

  done clear
  D)

  	I.	II.	III.	IV.
  	\[Ni{{\left( CO \right)}_{4}}\]	\[[Pb{{\left( EDTA \right]}^{2-}}\]	\[{{[Ag{{\left( CN \right)}_{4}}]}^{3-}}\]	\[{{[Zn{{(CN)}_{4}}]}^{2-}}\]

  done clear
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• question_answer64)
  The method of zone refining of metals is based on the principle of:
  A)
  Greater solubility of the impurity in the molten state than in the solid done clear
  B)
  Greater mobility of the pure metal than that of the impurity done clear
  C)
  Higher melting point of the impurity than that of the pure metal done clear
  D)
  Greater noble character of the solid metal than that of the impurity done clear
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• question_answer65)
  \[{{\Delta }_{f}}G{{~}^{-}}vs\]T plot in the Ellingham diagram slopes downward for the reaction
  A)
  \[Mg+\frac{1}{2}{{O}_{2}}\to MgO~\] done clear
  B)
  \[2Ag+\frac{1}{2}{{O}_{2}}\to A{{g}_{2}}O\] done clear
  C)
  \[C+\frac{1}{2}{{O}_{2~}}\to CO\] done clear
  D)
  \[CO+\frac{1}{2}{{O}_{2~}}\to C{{O}_{2}}\] done clear
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• question_answer66)
  Purification of silicon element used in semiconductors is done by
  A)
  zone refining       done clear
  B)
  heating done clear
  C)
  froth floatation   done clear
  D)
  heating in vacuum done clear
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• question_answer67)
  In the electrolysis of alumina to obtain aluminiumb metal, cryolite is added mainly to
  A)
  lower the melting point of alumina done clear
  B)
  dissolve alumina in molten cryolite done clear
  C)
  remove the impurities of alumina done clear
  D)
  increase the electrical conductivity done clear
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• question_answer68)
  Cassiterite is concentrated by
  A)
  levigation done clear
  B)
  electromagnetic separation done clear
  C)
  floatation done clear
  D)
  liquefaction done clear
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• question_answer69)
  Calcination is used in metallurgy for removal of?
  A)
  Water and sulphide done clear
  B)
  Water and \[C{{O}_{2}}\] done clear
  C)
  \[C{{O}_{2}}\] and \[{{H}_{2}}S\] done clear
  D)
  \[{{H}_{2}}O\] and \[{{H}_{2}}S\] done clear
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• question_answer70)
  Which of the following metals is extracted by the electrometallurgical method?
  A)
  Cu                    done clear
  B)
  Fe    done clear
  C)
  Na                    done clear
  D)
  Ag done clear
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