Tag: study of kerala

Questions Related to study of kerala

Process in which the extraction of metals from ores is called:

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. metallurgy

  2. mining

  3. refining

  4. none of these

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Correct Option: A
Explanation:

The process containing the extraction or refining of metals is known as metallurgy.

In metallurgy, the concentration of ore is followed by the dressing of ore.

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. True

  2. False

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Correct Option: B
Explanation:
Dressing of ore is followed by concentration of ore. 
Steps of metallurgy  are:
  • Crushing of the ore
  • Concentration of ore also known as Dressing of the ore
  • Conversion of concentrated ore to oxide 
  • Reduction of oxide to metal 
  • Refining of metal or Purification
Phosphorus mostly exists in free state.
geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. True

  2. False

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Correct Option: B
Explanation:

The given statement is false.
Phosphorus does not exists in free state. It mostly exists in combined state. It occurs in the minerals of apetite family such as fluorapatite $\displaystyle Ca _9[PO _4] _6CaF _2$ which is main constituent of phosphate rocks. Phosphorous is essential constituent of animal and plant matter.

Which of the following oxides react to form slag in open hearth process?

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. $CaO,CO$

  2. ${ P } _{ 2 }{ O } _{ 4 }, CaO$

  3. ${ P } _{ 2 }{ O } _{ 5 }, Si{ O } _{ 2 }$

  4. $CaO, { CO } _{ 2 }$

Show answer
Correct Option: A
Explanation:
${CaCO _3} _{(s)}\longrightarrow CaO _{(s)}+{CO _2} _{(g)}$
$SiO _2+CaO \longrightarrow {CaSiO _3} _{(slag)}$
The calcium oxide formed by the decomposition reacts with various acidic impurities in the iron (mainly silica) to form slag which is essentially calcium silicate $(CaSiO _3)$ .

Which metal is obtained as by-products during metallurgy of Lithium ?

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. Rubidium

  2. Caesium

  3. Both Rubidium and Caesium

  4. None of the above

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Correct Option: B

Identify $x,\ y \ and \ z$ for the following metallurgical process :


$Metal\ sulphide\overset { x }{ \rightarrow  } Metal\ oxide\overset { y }{ \rightarrow  } Impure\ metal$

$x,\ y$ and $z$ are respectively :

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. roasting, smelting, electrolysis

  2. roasting, calcination, smelting

  3. calcination, auto-reduction, basemerisation

  4. None of the above

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Correct Option: A
Explanation:

Roasting $\rightarrow $ It is a process in metallurgy
in which sulphide are is heated in 
air and transforms into oxides.

Smelting $\rightarrow $ It is a process of extracting
a base metal from corresponding
metal oxides.

electrolysis $ \rightarrow $ It is used in metallurgical
process, such as in extraction or purification
of metals from ores or compounds.

Therefore, the correct option is A.

Which of the following is NOT calcination?

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. $Fe(OH) _3.xH _2O\rightarrow Fe _2O _3+H _2O$

  2. $CuCO _3.Cu(OH) _2\rightarrow^ 2CuO+CO _2+H _2O$

  3. $CaCO _3\rightarrow^ CaO+CO _2$

  4. $(NH _4) _2CO _3\rightarrow^ 2NH _3+CO _2+H _2O$

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Correct Option: D
Explanation:

Calcination is a process of heating to high temperature in air or oxygen, however calcination is also used to mean a thermal treatment process in the absence or limited supply of air or oxygen.

$(NH _4) _2CO _3$ is not an ore.so, it do not undergo calcination.

Which of the following element is found in its native state?

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. Silver

  2. Gold

  3. Sodium

  4. Both (A) and (B)

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Correct Option: D
Explanation:

Silver and Gold occur in native state (free state). 

 
These elements have very low reactivity and are not attacked by oxygen or air, moisture, carbon dioxide or other non metals.

In the extraction of iron slag, which of the following is formed during extraction of iron?

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. $Fe _3C$

  2. $FeSiO _3$

  3. $MgSiO _3$

  4. $CaSiO _3$

Show answer
Correct Option: D
Explanation:

Reaction to form slag
$CaO+SiO _2\rightarrow CaSiO _3$ (slag)

Which of the following statements is correct regarding the slag formation during extraction of a metal like copper or iron?

geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

  1. The slag is lighter and lower melting than the metal.

  2. The slag is heavier and lower melting than the metal.

  3. The slag is lighter and higher melting than the metal.

  4. The slag is heavier and higher melting than the metal.

Show answer
Correct Option: A
Explanation:

Slag formed in extraction of metals are lighter and having low melting point than metal so they generally appear in upper layer of solutions.