Tag: production of metals

Questions Related to production of metals

Carbon cannot be used to produce magnesium by chemical reduction of $MgO$ because:

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

  1. carbon is not a powerful reducing agent

  2. magnesium reacts with carbon to form carbides

  3. magnesium is less electropositive than carbon

  4. carbon does not react with magnesium

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Correct Option: B

Which of the following metals occurs in nature principally oxide ores.

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

  1. $Ca$

  2. $Co$

  3. $Cr$

  4. $Cu$

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Correct Option: A
Explanation:
$Ca$ occurs aa calcium oxide.So the naturally occuring oreof calcium is calcium oxide $ CaO$.
Hence option A is correct.

When $FeCr _2O _4$ (chromite) is reduced with Carbon in an electric-arc furnace:

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

  1. Cr and $Fe _2O _3$ are formed

  2. Fe and $Cr _2O _3$ are formed

  3. Fe and Cr (ferrochrome) are formed

  4. $FeCrO _4$ is formed

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Correct Option: C
Explanation:

When chromite $(FeCr _2O _4)$ is reduced with carbon in an electric-arc furnace, ferrochrome (Fe and Cr) is obtained.

Carbon reduction process is not comrnerically applicable for which of the following set of oxides to extract the respective metal?
(I) ZnO  (II)$Fe _2O _3$   (III)$Al _2O _3$  (IV) $SnO _2$  (V) MgO

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

  1. $ZnO, Fe _2O _3, SnO _2$

  2. $ZnO, SnO _2, MgO$

  3. $MgO, AI _2O _3$

  4. $MgO, SnO _2, Al _2O _3$,

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Correct Option: C
Explanation:

Carbon reduction process is used to reduce less electropositive metals.
$Mg, Al$ have high electropositivity. Hence, cannot be extracted from oxides through carbon reduction process.

Carbon can be used to reduce the number of oxides and other compounds, and because of the low cost and availability of coke, this method is widely used. But the disadvantages are that:

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

  1. high temperature is needed, which is expensive

  2. many metals combine with carbon to form carbides

  3. low temperature is needed, which is expensive

  4. many metal combine with carbon and do not form carbides

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Correct Option: A,B

Metals which can be obtained by carbon reduction of their oxides are _________.

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

  1. Cu

  2. Fe

  3. Al

  4. Pb

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Correct Option: A,B,D
Explanation:

 Aluminium being more electropositive than carbon, hence it is not reduced by carbon. Other metal oxides can be reduced by carbon.

From the following identify the correct ones.

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

  1. $Fe _2O _3 + 3CO \rightarrow 2Fe + 3CO _2$

  2. $ZnO + C \rightarrow Zn + CO$

  3. $Ca _3(PO _4) _2 + C \rightarrow P$

  4. $PbO + C \rightarrow Pb$

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Correct Option: A,B,D
Explanation:

The correct reactions are as follows-

$Fe _2O _3+3CO\longrightarrow 2Fe+3CO _2$ in Blast furnace.
$ZnO+C\longrightarrow Zn+CO$
$PbO+C\longrightarrow Pb$
$ZnO+C$ and $PbO+C$ can be reduced with carbon.

Lead is extracted from its chief ore galena by both carbon reduction as well as self-reduction.
chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

  1. True

  2. False

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Correct Option: A
Explanation:

$2PbS+3O _2\rightarrow 2PbO+2SO _2$
$PbS+2PbO\rightarrow 3Pb+SO _2$ (self reduction)
$PbO+C\rightarrow Pb+CO$
$PbO+CO\rightarrow Pb+CO _2$ (carbon reduction)

Identify the metal $M$ whose extraction is based on the following reactions:
$MS+2{ O } _{ 2 }\longrightarrow M{ SO } _{ 4 }$
$2MS+3{ O } _{ 2 }\longrightarrow 2MO+2S{ O } _{ 2 }$
$MS+2MO\longrightarrow 3M+S{ O } _{ 2 }$
$MS+M{ SO } _{ 4 }\longrightarrow 2M+2S{ O } _{ 2 }\quad $

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

  1. magnesium

  2. aluminium

  3. lead

  4. tin

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Correct Option: A

Which of the following oxides cannot be reduced to metal by carbon?

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

  1. $ZnO$

  2. $Al _2O _3$

  3. $CuO$

  4. $CaO$

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Correct Option: B,D
Explanation:

Generally carbon is more reactive than $Zn$ and $Cu$. Hence, $ZnO$ and $CuO$ can be reduced by carbon leading to the formation of corresponding metals,  but carbon is less reactive than $Ca$ and $Al$, so $CaO$ and $Al _2O _3$ can not be reduced by carbon .