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Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

In the extraction of copper, metal is formed in the Bessemer converter due to a reaction:-

  1. ${Cu _2S+2Cu _2O\rightarrow 6Cu+SO _2}$
  2. ${Cu _2S\rightarrow 2Cu+S}$
  3. ${Fe+Cu _2O\rightarrow 2Cu+FeO}$
  4. ${2Cu _2O\rightarrow 4Cu+O _2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In the extraction of copper, metal is formed in the Bessemer converter due to self reduction.

Reaction:
$Cu _2S + 2Cu _2O \longrightarrow 6Cu + SO _2$
Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy
The slag obtained during the extraction of copper pyrites is composed mainly of ${ FeSiO } _{ 3 }$.

  1. True

  2. False
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A Correct answer
Explanation

Copper is mainly extracted from copper pyrites. After the concentration of its ore by froth flotation process, the ore is roasted in a current of air to remove arsenic, antimony and much of sulphur.

The ore is then mixed with a little coke and sand and smelted in a water-jacketed blast furnace. The minor reactions that occured during roasting continue here. Ferrous oxide combines with sand to form a fusible slag.

$FeO + SiO _2 \rightarrow FeSiO _3$ slag

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Copper is extracted from the ore copper pyrite by smelting in a blast furnace. The flux used and the slag formed are :

  1. flux $CaO$, slag $CaSiO _3$
  2. flux $SiO _2$, slag $CaSiO _3$
  3. flux $FeO$, slag $FeSiO _3$
  4. flux $SiO _2$,slag $FeSiO _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Copper is extracted from the ore copper pyrite by smelting in a blast furnace. The flux used is  $SiO _2$ and slag formed is $FeSiO _3$.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Chloroform on reduction with zinc dust and water gives

  1. Methyl chloride

  2. Dichloro methane

  3. Chloro methane

  4. Methane
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\underset{\displaystyle chloroform}{CHCl _3}\overset{\displaystyle 6[H]; Zn/H _2O}{\underset{\underset {\displaystyle -ZnCl _2}{-HCl}}{\displaystyle \rightarrow}}\underset{\displaystyle methane}{CH _4}$.
Chloroform on reduction with Zn and HCl gives dichloromethane $(CH _2Cl _2)$.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Polling process is employed for the removal of:

  1. $Cu _2O\ from \ Cu$
  2. $Al _2O _3\ from\ Al$
  3. $Fe _2O _3\ from\ Fe$

  4. None of the above.
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A Correct answer
Explanation

Polling is a metallurgical method employed in the purification of copper which contains cuprous oxide as an impurity. 

In the past, freshly cut trees were used as wooden poles. The sap in these poles acted as the reducing agent. The heat of the copper makes the pole emit a gas that reduces the cuprous oxide to copper.