Tag: basics of metallurgy

Questions Related to basics of metallurgy

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.

When a solid melts, the temperature:

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

  1. increases

  2. decreases

  3. remains same

  4. can't say

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Correct Option: C
Explanation:

When a solid melts the temperature remains same until the whole solid melts.

During melting of ice, the temperature of the ice does not change until the ice melts. The heat is used up in :

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

  1. changing the state overcoming the forces of attraction

  2. changing the state without overcoming the forces of attraction

  3. releasing into atmosphere

  4. None of the above

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Correct Option: A
Explanation:

The heat is used up in changing the state overcoming the forces of attraction.

Which of the following method is used for extracting metals from ores?

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

  1. Reduction

  2. Melting

  3. Electrolysis

  4. Both $A$ and $C$

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Correct Option: D
Explanation:

The compounds of reactive metals from which metals extracted and purified are called ores of metals. Metals can be extracted from ore by reduction and electrolysis.

Prior to reduction, metal sulphide and carbonates are converted into oxides because:

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

  1. carbonates, sulphides are heavy molecules

  2. it is easier to obtain a metal from its oxide as compared to its sulphides and carbonates

  3. it is easy to heat oxide compared to sulphides and carbonates

  4. both $A$ and $B$

Show answer
Correct Option: B
Explanation:

It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted to metal oxides.