Tag: production of metals

Questions Related to production of metals

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

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

  1. $Cu _2S$

  2. $FeS$

  3. $HgS$

  4. $ZnS$

Show answer
Correct Option: B
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 $Fe$. 

Which of the following reactions show the process of smelting?

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

  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. $2HgS + 3O _2\rightarrow 2HgO+2SO _2$

Show answer
Correct Option: C
Explanation:

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

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.

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

  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

Show answer
Correct Option: B
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.

Extraction of chlorine from brine is based on:

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

  1. reduction

  2. displacement

  3. oxidation

  4. evaporation

Show answer
Correct Option: C
Explanation:
In the extraction of chlorine by electrolysis of brine, oxidation of ${ Cl }^{ - }$ ion to chlorine gas occurs.
$2{ Cl }^{ - }+2{ H } _{ 2 }O\rightarrow 2{ OH }^{ - }+{ H } _{ 2 }+{ Cl } _{ 2 }$

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

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

  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. $Cu _2O+\frac{1}{2}Cu _2S\rightarrow 2Cu+\frac{1}{2}SO _2$

Show answer
Correct Option: D
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.
$2Cu _2S+3O _2\rightarrow 2Cu _2O+3SO _2$
$2Cu _2O+Cu _2S\rightarrow 6Cu+ SO _2$

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].

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

  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. $[Au(CN) _4]^-, [Zn(CN) _4]^{2-}$

Show answer
Correct Option: A
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
$X={ \left[ Au{ \left( CN \right)  } _{ 2 } \right]  }^{ - }$ & $Y={ \left[ Zn{ \left( CN \right)  } _{ 4 } \right]  }^{ 2- }$

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

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

  1. Pyrometallurgy

  2. Hydrometallurgy

  3. Both a and b

  4. None of above

Show answer
Correct Option: A
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.

Metals more reactive than carbon are usually extracted by_________.

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

  1. Pyrolysis

  2. Electrolysis

  3. Fractional distillation

  4. Filteration

Show answer
Correct Option: B
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. 

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

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

  1. Electro-refining

  2. Electrowinning

  3. Both a and b

  4. Oxidation

Show answer
Correct Option: C
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. 

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

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

  1. Using sodium hydroxide

  2. Using electrolysis

  3. Froth flotation method

  4. None of above

Show answer
Correct Option: C
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.