Tag: extraction of metals from ore

Questions Related to extraction of metals from ore

Lead obtained from galena ore (PbS) by air reduction or carbon reduction process contains base metal (Cu, Bi, As, Sn, Zn) as impurities. Gelatin acts as an addition agent in the electrolysis of Pb. In the presence of gelatin, Pb becomes :

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

  1. hard and brittle

  2. soft and rubbery

  3. smooth and uniform

  4. only brittle

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Correct Option: C
Explanation:
Lead obtained contains impurities like $Cu, Sb, Sn, As, Ag, Au, etc.$ which make it hard. During electrolytic refining of lead, the electrolyte $(PbSiF _6+H _2SiF _6)$ is mixed with a little gelatin. Gelatin is added for smooth and uniform deposition of lead in this process. 

Hence, the correct option is (C).

Which of the following metal oxides are reduced by self reduction method?

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

  1. $Cu _2O$

  2. $PbO$

  3. $HgO$

  4. $CaO$

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Correct Option: A,B,C
Explanation:

Self-reduction process:  This process is also called auto reduction process or air reduction process. 


The sulphide ores of less electropositive metals like Hg, Pb, Cu etc. are heated in the air as to convert part of the ore into oxide or sulphate which then reacts with the remaining sulphide ore to give the metal and sulphur dioxide. 


No external reducing agent is used in this process.

Hence options A,B & C are correct options.

Pb is a very important element of carbon family. It forms a number of compounds which are very useful in industries. The process of removal of base metals (Cu, Sn, Bi, As) from lead is called:

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

  1. softening process

  2. liquation

  3. parke's process

  4. cupellalion

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Correct Option: A
Explanation:

For the removal of base metals the impure bullion is charged to a softening furnace whereby oxidation these elements form drosses or slags and, with some lead, are skimmed from the bath. This is the softening process. 

Aquaregia is ___ part conc. HCI and ___ part conc. $HNO _3$.

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

  1. one,three

  2. one,one

  3. three,three

  4. three,one

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Correct Option: D
Explanation:

Aqua regia is three parts conc. $ HCI$ and one part conc. $HNO _3$.


$HNO _3 + 3HCl \rightarrow NOCl + 2H _2O + 2CI$

So, the correct option is $D$

The main source of lead is PbS. It is converted to Pb by:- 


(i) ${PbS\xrightarrow[\Delta]{air }PbO+SO _2\xrightarrow[\Delta]{C}Pb+CO _2}$


(ii) ${PbS\xrightarrow[\Delta]{air }PbO+PbS\xrightarrow[]{\Delta}Pb+SO _2}$ 

Self reduction process is:
chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

  1. i

  2. ii

  3. both

  4. none

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Correct Option: B
Explanation:

Self reduction process of Pb is

$PbS + 2PbO \rightarrow   3Pb + SO _2$
so (ii) is self reduction process.

Which of the following reduction processes are correct?

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

  1. ${Fe _2O _3+C\overset{Reduction}{\rightarrow}Fe}$

  2. ${ZnO+C\overset{Reduction}{\rightarrow}Zn}$

  3. ${SnO _2+C\overset{Reduction}{\rightarrow}Sn}$

  4. ${PbO+C\overset{Reduction}{\rightarrow}Pb}$

Show answer
Correct Option: A,B,C,D
Explanation:

Reduction is loss of oxygens.
In all the above reactions the metal oxides are reduced to metals by the elimination of oxygens,so all are reduction ractions.
Hence options A,B,C & D are correct.

Which one of the following metals can not be extracted by using Al as a reducing agent ________________.

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

  1. $\displaystyle Na$ from $\displaystyle { Na } _{ 2 }O$

  2. $\displaystyle Cr$ from $\displaystyle { Cr } _{ 2 }{ O } _{ 3 }$

  3. $\displaystyle Mn$ from $\displaystyle { MnO } _{ 2 }$

  4. $\displaystyle Fe$ from $\displaystyle { Fe } _{ 2 }{ O } _{ 3 }$

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Correct Option: A
Explanation:

As sodium  (alkali metal) is more reactive than Al so it cannot be extracted from $Na _2O$ by using Al as a reducing agent.

Metals can be recovered from their ores by chemical methods.

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:

Metals can be recovered from their ores by following chemical methods:

Calcination, Leaching, Roasting etc.

Sequence the following steps involved generally in the extraction of a metal in pure form from its ore.
(a) The metal obtained from its oxide require further purification for end use.
(b) The ore should be converted to its oxide form.
(c) The ore is beneficial to us if it is handpicked then metal crushed and ground, and later subjected to pulverization as per the requirement
(d) The ore in the form of oxide is required to be reduced.
(e) Dressed ore is required for it to be concentrated.

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

  1. e c b d a

  2. c e b d a

  3. c e b a d

  4. c e d b a

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Correct Option: B
Explanation:

(c) The ore is beneficial to us if it is handpicked then metal crushed and ground, and later subjected to pulverization as per the requirement
(e) Dressed ore is required for it to be concentrated.
(b) The ore should be converted to its oxide form.
(d) The ore in the form of oxide is required to be reduced.
(a) The metal obtained from its oxide require further purification for end use.

The process in which the state of a substance changes from solid to liquid is called:

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

  1. boiling

  2. condensation

  3. freezing

  4. melting

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Correct Option: D
Explanation:

Melting is the process in which a substance changes from solid to liquid.