Tag: production of metals

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Questions Related to production of metals

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following sulphides when  heated strongly in air gives the corresponding metal without undergoing separate reduction of oxide?

  1. $Cu _2S$
  2. $FeS$
  3. $HgS$
  4. $ZnS$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$2Cu _2S+3O _2\longrightarrow 2Cu _2O+2SO _2$

$2ZnS+3O _2\longrightarrow 2ZnO+2SO _2$
$2PbS+3O _2\longrightarrow 2PbO+2SO _2$
$2HgS+3O _2\longrightarrow 2HgO+2SO _2$
$FeS+O _2\longrightarrow Fe+SO _2$
$FeS$ when heated directly in air gives $Fe$. 

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following reactions show the process of smelting?

  1. $2PbO + PbS \rightarrow 3Pb + SO _2$
  2. $2Na[Au(CN) _2]+Zn \rightarrow Na _2[Zn(CN) _4]+2Au$
  3. $PbO+C\rightarrow Pb + CO$
  4. $2HgS + 3O _2\rightarrow 2HgO+2SO _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon reduction occurs in smelting from oxide ore. $PbO+C\longrightarrow Pb+CO$

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Fill in the blanks with the correct choice.
The undesired impurities present in the ores are called (i). To remove the volatile impurities from the ore, the (ii) process is carried out. Flux combines with non-fusible impurities to form (iii). $CaO$ acts as a (iv) flux.

  1. (i) - gangue, (ii) -roasting, (iii) - slag, (iv) -acidic

  2. (i) - gangue, (ii) - calcination, (iii) - slag, (iv) - basic

  3. (i) - anode mud, (ii) - leaching, (iii) - matrix, (iv) -acidic

  4. (i) - gangue, (ii) -roasting, (iii) - solution, (iv) -acidic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$(i)$ The undesired impurities present in the ores are called gangue.
$(ii)$ To remove the volatile impurities from the ore calcination is carried out.
$(iii)$ Flux combines with non-fusible impurities to form slag.
$(iv)$ $CaO$ acts as basic flux.
Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Extraction of chlorine from brine is based on:

  1. reduction

  2. displacement

  3. oxidation

  4. evaporation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
In the extraction of chlorine by electrolysis of brine, oxidation of ${ Cl }^{ - }$ ion to chlorine gas occurs.
$2{ Cl }^{ - }+2{ H } _{ 2 }O\rightarrow 2{ OH }^{ - }+{ H } _{ 2 }+{ Cl } _{ 2 }$
Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following is reactions is an example of autoreduction? 

  1. $Fe _3O _4+4CO\rightarrow 3Fe+4CO _2$
  2. $CuO+C\rightarrow 2Cu+CO$
  3. $Cu^{2+} _{(aq)}+Fe _{(s)}\rightarrow Cu _{(s)}+Fe^{(2+)} _{(aq)}$
  4. $Cu _2O+\frac{1}{2}Cu _2S\rightarrow 2Cu+\frac{1}{2}SO _2$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The sulphide ores of certain less electropositive metals like those of Hg, Pb, Cu, etc. when heated in air bring about the conversion of a part of the sulphide ore to oxide or sulphate which then reacts with the remaining sulphide to give the matal and $SO _2$. No external reducing agent is used in this process.
$2Cu _2S+3O _2\rightarrow 2Cu _2O+3SO _2$
$2Cu _2O+Cu _2S\rightarrow 6Cu+ SO _2$

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

In the process of extraction of gold, Roasted gold ore$+CN^- _{(aq)}+H _2O\overset{O _2}{\rightarrow}[X]+[OH^-]$, $[X]+Zn\rightarrow [Y]+Au$
Identify the complexes [X] and [Y].

  1. $[Au(CN) _2]^-, [Zn(CN) _4]^{2-}$
  2. $[Au(CN) _4]^{3-}, [Zn(CN) _4]^{2-}$
  3. $[Au(CN) _2]^{2-}, [Zn(CN) _6]^{4-}$
  4. $[Au(CN) _4]^-, [Zn(CN) _4]^{2-}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$4Au+8{ CN }^{ - }+2{ H } _{ 2 }O+{ O } _{ 2 }\longrightarrow 4{ \left[ Au{ \left( CN \right)  } _{ 2 } \right]  }^{ - }+4{ OH }^{ - }$
$2{ \left[ Au{ \left( CN \right)  } _{ 2 } \right]  }^{ - }+Zn\longrightarrow 2Au+{ \left[ Zn{ \left( CN \right)  } _{ 4 } \right]  }^{ 2- }$
It is Mc-Arthur process. Here
$X={ \left[ Au{ \left( CN \right)  } _{ 2 } \right]  }^{ - }$ & $Y={ \left[ Zn{ \left( CN \right)  } _{ 4 } \right]  }^{ 2- }$
Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following technique uses high temperature to convert ore into raw metals?

  1. Pyrometallurgy

  2. Hydrometallurgy

  3. Both a and b

  4. None of above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

After the ore is mined, the metals must be extracted, usually by chemical or electrolytic reduction. Pyrometallurgy uses high temperatures  to convert ore into raw metals, while hydrometallurgy employs aqueous treatment for the same purpose.

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Metals more reactive than carbon are usually extracted by_________.

  1. Pyrolysis

  2. Electrolysis

  3. Fractional distillation

  4. Filteration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Metals more reactive than carbon are usually extracted by electrolysis. Electrolysis is the process of breaking down a compound using electrical energy and is needed to extract  the most reactive metals. 

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

What is the most common type of electrometallurgical processes to obtain pure metal?

  1. Electro-refining

  2. Electrowinning

  3. Both a and b

  4. Oxidation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The most common types of electrometallurgical processes are electrowinning and electro-refining. Electrowinning is an electrolysis process used to recover metals in aqueous solution, usually as the result of an ore having undergone one or more hydrometallurgical processes. Electro-refining is used to dissolve an impure metallic anode and produce a high purity cathode. 

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following is a physical mean for concentration of ore?

  1. Using sodium hydroxide

  2. Using electrolysis

  3. Froth flotation method

  4. None of above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In many cases, it is possible to separate the metal compound from unwanted rocky material by physical means. A common example of this involves froth flotation. In this method, the unwanted object binds with air and comes on the surface as bubbles.