Tag: chemistry

Questions Related to chemistry

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).

Show answer
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

Show answer
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.
$ZnC{ O } _{ 3 }(s)\xrightarrow { heat } ZnO(s)+C{ O } _{ 2 }(g)$

$Cu _{2}S+2Cu _{2}O \rightarrow 6Cu+SO _{2}$
In which process of metallurgy of copper, above equation is involved -

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

  1. roasting

  2. self reduction

  3. refining

  4. purification

Show answer
Correct Option: B
Explanation:

During the Bessemerisation process, the sulphide ores of less electropositive metals are heated in air to convert part of the ore into oxide or sulphate which then react with the remaining sulphide ore to give the metal and sulphur dioxide.
Copper sulphide is partially oxidised to cuprous oxide which futher can react with remaining copper sulphide to form copper and sulphur dioxide.
$2Cu _{2}S+3O _{2} \rightarrow 2Cu _{2}O+2SO _{2}$
$Cu _{2}S+2Cu _{2}O \rightarrow 6Cu+SO _{2}$
This process is also called  autoreduction process or air reduction process. 

Which of the following two substances react to produce blister copper?

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

  1. $Cu _{2}S _{(s)}$ and $Cu _{2}O _{(s)}$

  2. $Cu _{2}O _{(s)}$ and $FeS _{(s)}$

  3. $Cu _{2}S _{(s)}$ and $O _{2(g)}$

  4. $Cu _{2}S _{(s)}$ and $FeS _{2(s)}$

Show answer
Correct Option: A
Explanation:

Blast of air converts $Cu _2S$ partly into $Cu _2O$ which reacts with remaining $Cu _2S$ to give molten copper. The copper so obtained is called "Blister copper" because, as it solidifies, $SO _2$ hidden in it escapes out producing blister on its surface

option A is correct

In the extraction of copper, the copper matte is a mixture of:

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

  1. copper (II) sulphide and iron (II) sulphide

  2. copper (II) sulphide and iron (III) sulphide

  3. copper (I) sulphide and iron (II) sulphide

  4. copper (I) sulphide and iron (III) sulphide

Show answer
Correct Option: A
Explanation:
  • The chemical formula of copper matte is $Cu _2S+FeS$. It is a combination of copper sulphide and iron sulphide.
  • It is a phase in which extracted metal is converted into crude metal which is a final product.
  • $80-70\%$ of copper matte is used $80-95\%$. $5- 17\%$ metallic copper, $Fe-Co$ alloy etc are used.

Metallurgical process of zinc involves roasting of zinc sulphide followed by reduction. Metallic zinc distills over as it is volatile and impurities like Cu, Pd and Fe gets condensed. The crude metal obtained is called spelter, which may be purified by:

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

  1. electrolysis process

  2. fractional distillation

  3. polling

  4. heating with iodine

Show answer
Correct Option: A,B
Explanation:

Spelter Zn is purified by both distillation and electro fining process(here we get more pure Zn).

Metal(s) which can be extracted by smelting process is/are:

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

  1. Pb

  2. Fe

  3. Zn

  4. Al

Show answer
Correct Option: A,B,C
Explanation:

Smelting is used to produce a metal from its ore. This includes iron extraction from iron ore, copper extraction, and other base metals from their ores like lead and zinc. 

Blister copper is refined by stirring molten impure metal with green logs of wood because such wood liberates hydrocarbon gases (like $CH _{4}$). Name the process involved.

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

  1. Cupellation

  2. Poling

  3. Scaling

  4. Oxidation

Show answer
Correct Option: B
Explanation:

Blister copper contain $Cu _2O$ as impurity and is refined by poling process. 


In this process, the molten impure metal is stirred with green logs of wood because such a wood liberates hydrocarbon gases (like  $CH _{4}$), and hence, act as a reducing agent to reduce copper oxide to metal.


Option B is correct.

Self-reduction of CuS to Cu can be carried out in:

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

  1. Bessemer converter

  2. Pierce-Smith converter

  3. both (a) and (b)

  4. None of the above

Show answer
Correct Option: C
Explanation:

Self-reduction of CuS to Cu can be carried out in either Bessemer converter or Pierce-Smith converter.
$2Cu _2S+3O-2 \rightarrow 2Cu _2O + 2SO _2$
$2Cu _2O+Cu _2S \rightarrow 6Cu+SO _2$