Tag: basics of metallurgy

Questions Related to basics of metallurgy

Copper, which is extracted from cuprite, is a/an :

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

  1. sulphide ore

  2. carbonate ore

  3. oxide ore

  4. halide ore

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Correct Option: C
Explanation:

Cuprite is an oxide mineral composed of copper(II) oxide ($Cu _2O$), and is a minor ore of copper. It can yield small gemstones.

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

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

  1. flux $CaO$, slag $CaSiO _3$

  2. flux $SiO _2$, slag $CaSiO _3$

  3. flux $FeO$, slag $FeSiO _3$

  4. flux $SiO _2$,slag $FeSiO _3$

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Correct Option: D
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 $FeSiO _3$.

Copper is extracted by the method:

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

  1. Self-reduction

  2. Carbon reduction

  3. Oxidation-reduction

  4. None of these

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Correct Option: A
Explanation:

Copper is obtained from its one by process of self reduction or intoreduction.
$Cu _2S+2Cu _2O \rightarrow 6Cu+SO _2$

Willemite is

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

  1. $Zn _2SiO _4$

  2. $H _2PtCl _6$

  3. $ZnO$

  4. $ZnOFe _2O _3$

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Correct Option: A
Explanation:

Chemical formula of willemite is Zn₂SiO₄

Chloroform on reduction with zinc dust and water gives

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

  1. Methyl chloride

  2. Dichloro methane

  3. Chloro methane

  4. Methane

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Correct Option: D
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 $(CH _2Cl _2)$.

Zinc spelter is the purest form of zinc.

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

  1. True

  2. False

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Correct Option: B
Explanation:

Spelter zinc is an alloy of equal parts copper and zinc, i.e. a brass, used for hard soldering and brazing, or as an alloy, containing lead, that is used instead of bronze.

Hence, it is not the purest form of zinc.

Polling process is employed for the removal of:

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

  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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Correct Option: A
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. 

When copper ore is mixed with silica, in a reverberatory furnace copper matte is produced. The copper matte contains:

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

  1. Sulphides of copper (II) and iron (II)

  2. Sulphides of copper (II) and iron (III)

  3. Sulphides of copper (I) and iron (II)

  4. Sulphides of copper (I) and iron (III).

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Correct Option: A

High purity copper metal is obtained by:

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

  1. carbon reduction

  2. hydrogen reduction

  3. electrolytic refining

  4. thermite reduction

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Correct Option: C
Explanation:

In extraction of copper:
In final step electrolytic refining process is used to 99.99% pure copper metal.

The balance reaction involved during extraction of zinc from its ore, by calcination of zinc ore, is:

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

  1. $2ZnCO _{3} (s) \xrightarrow{Heat} 2ZnO(s) + CO _{2}(g)$

  2. $ZnCO _{3} (s) \xrightarrow{Heat} ZnO(s) + CO _{2}(g)$

  3. $ZnCO _{3} (s) \xrightarrow{Heat} 2ZnO(s) + CO _{2}(g)$

  4. none of these

Show answer
Correct Option: B
Explanation:

Calcination is defined as heating to high temperatures in the presence of air or oxygen. Heating the metal carbonates result in the formation of metal oxides and carbon dioxide.
$ZnC{ O } _{ 3 }(s)\xrightarrow { heat } ZnO(s)+C{ O } _{ 2 }(g)$