Tag: chemistry

Questions Related to chemistry

Which of the following processes is involved in the smelting process?

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

  1. $ZnCO _{3} \rightarrow ZnO + CO _{2}$

  2. $PbS + 3O _{2} \rightarrow 2PbO + 2SO _{2}$

  3. $Fe _{2}O _{3} + 3C \rightarrow 2Fe + 3CO$

  4. $ Al _{2} O _{3}. 2H _{2}O \rightarrow Al _{2}O _{3} + 2H _{2}O$

Show answer
Correct Option: C
Explanation:

In smelting process, ferric oxide gets reduced to Iron with the help of coke. The redox reaction is given by the option C.

In the metallurgical extraction of iron, which of the following processes takes place in reverberatory furnace?

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

  1. Conversion of iron oxide to iron

  2. Conversion of cast iron to wrought iron

  3. Conversion of cast iron to steel

  4. Conversion of pig iron to cast iron

Show answer
Correct Option: B
Explanation:

Wrought iron or malleable iron is the purest form of commercial iron and is prepared from cast iron by oxidising impurities in a reverberatory furnace lined with haematite.

Compound $X$ and aluminium are used to join railway tracks.
Name the reaction.

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

  1. Galvanic reaction

  2. Thermal reaction

  3. Thermite reaction

  4. Combination reaction

Show answer
Correct Option: C
Explanation:

The reaction is called thermite reaction, in which $Al$ reduces the oxide of another metal as it forms stronger and more stable bonds with oxygen than the other metal.

$Fe _2O _3 + 2 Al \rightarrow  2 Fe + Al _2O _3$

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 $A$