Tag: general principles and processes of isolation of elements

Questions Related to general principles and processes of isolation of elements

The electrolytic reduction technique is used in the extraction of:

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. Metalliods

  2. Highly electro positive metals

  3. Transition metals

  4. Highly electronegative metals

Show answer
Correct Option: B
Explanation:

Oxides of strong elecropositive metals such as K, Ca, Na, Al and Mg are very stable. It is difficult to reduce them into metallic state by carbon reduction.
Such metals are extracted by passing electricity through their fued chlorides/oxides/hydroxides.
So electrolytic extraction technique is used in extraction of highly electro positive metals.

Which of the following oxides cannot be reduced by coke?

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. $Cu _2O,: K _2O$

  2. $Fe _2O,: ZnO$

  3. $CaO, : K _2O$

  4. $PbO,: Fe _3O _4$

Show answer
Correct Option: C
Explanation:

Oxides of strong elecropositive metals such as $K, Ca, Na, Al$ and $Mg$ are very stable. It is difficult to reduce them into metallic state by carbon reduction.
Such metals are extracted by passing electricity through their fused chlorides/oxides/hydroxides.

Which of the following is not correctly matched?

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. Red bauxite - Purification by Serpeck's method

  2. Iron from haematite - Carbon monoxide reduction

  3. Calamine - Carbonate ore

  4. $FeSiO _3$ - Slag obtained in the extraction of copper

Show answer
Correct Option: A

$Zn$ cannot displace following ions from ions of which aqueous solution?

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. $Ag^+$

  2. $Cu^{++}$

  3. $Fe^{++}$

  4. $Na^+$

Show answer
Correct Option: D
Explanation:

Among all given option only $Na^+$ has less reduction potential than Zn so it can not be reduced by Zn.

Which one of the following is not a method of concentration of ore? 

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. Electromagnetic separation

  2. Smelting

  3. Gravity separation

  4. Froth floatation process

Show answer
Correct Option: B
Explanation:

The process of removal of unwanted materials from the ore is known as ore concentration. 


Froth floatation, electromagnetic separation, and gravity separation are few of the processes used for ore concentration.

 
Smelting, however, is a process of heating the ore in order to extract the base metal. 


Hence B is the correct answer

Name the substance which remains in a test tube after heating ferrous sulphate.

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. $Fe _2O _3$

  2. $Fe _2S$

  3. $Fe _2(SO _4) _3$

  4. None of these

Show answer
Correct Option: A
Explanation:

Heating farrow sulfate in a test tube following reaction takes place

$FeSO _4.7H _2O\rightarrow Fe SO _4+7H _2O$
$2Fe SO _4\rightarrow Fe _2O _3+SO _2+SO _3$
Both $SO _2$ and $SO _3$ are gases that colorless and evolved out 
Only $Fe _2O _3$  that is ferric oxide which reddish brown in colour remained in the fort tube ,so the answer is $Fe _2O _3$ that is ferric oxide

Heating mixture of $Cu _2O$ and $Cu _2S$ will give:

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. $Cu+SO _2$

  2. $Cu+SO _3$

  3. $CuO+CuS$

  4. $Cu _2O+S$

Show answer
Correct Option: A
Explanation:

Reaction of the process:


$ 2Cu _2 O+ Cu _2S \overset{\Delta}{\longrightarrow} 6Cu+SO _2$

The heating mixture of Cu$ _2$O and Cu$ _2$S will give Cu and SO$ _2$ mixture.

Hence, the correct option is $A$

The iron manufactured by pudding process is called an

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. Pig iron

  2. cast iron

  3. wrought iron

  4. white cast iron

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Correct Option: C

In extractive metallurgy of zinc partial fusion of ZnO with coke is called ______ and reduction of the ore to the molten metal is called________ .

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. sintering, smelting

  2. roasting, smelting

  3. sintering, roasting

  4. none of these

Show answer
Correct Option: A
Explanation:

Sintering is the process of forming a solid mass of material by heat and/or pressure without melting it to the point of liquefaction. Sintering happens naturally in mineral deposits or as a manufacturing process used with metals, ceramics, plastics, and other materials.

Smeltings main use is to produce a metal from its ore. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gasses or slag and leaving just the metal behind. The reducing agent is commonly a source of carbon.The carbon removes oxygen from the ore, leaving behind elemental metal. 

Carbon reduction method is employed for commercial extraction of :

thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. haematite

  2. cassiterite

  3. iron pyrite

  4. corundum

Show answer
Correct Option: A,B
Explanation:

In extraction of tin from cassiterite-
$SnO _2+2C\rightarrow Sn+2CO$

In extraction of iron from haematite -
$Fe _2O _3+3CO\rightarrow 2Fe+3CO _2$

Iron pyrite $FeS _2$ is a sulphide ore for which froth floatation method is used.
Corundum is a crystalline form of aluminium oxide $Al _2O _3$ with traces of iron, titanium and chromium; for which electrolytic reduction method is used.