Tag: study of kerala

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

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
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
Multiple choice geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala
Phosphorus mostly exists in free state.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. $CaO,CO$
  2. ${ P } _{ 2 }{ O } _{ 4 }, CaO$
  3. ${ P } _{ 2 }{ O } _{ 5 }, Si{ O } _{ 2 }$
  4. $CaO, { CO } _{ 2 }$
Reveal answer Fill a bubble to check yourself
A Correct answer
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 $(CaSiO _3)$ .
Multiple choice geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

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 :

  1. roasting, smelting, electrolysis

  2. roasting, calcination, smelting

  3. calcination, auto-reduction, basemerisation

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Which of the following is NOT calcination?

  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. $(NH _4) _2CO _3\rightarrow^ 2NH _3+CO _2+H _2O$
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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

  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.
Reveal answer Fill a bubble to check yourself
A Correct answer
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.