Tag: in the land of kerala

Quizzes (8) Questions (211)

Questions Related to in the land of kerala

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.

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

The combined state of metals are called:

  1. Mineral

  2. Gangue

  3. Flux

  4. Native form
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The metal found in nature occur in the free or combined state it is generally known as pure metals. A native metal is a metal found in metallic state naturally.  It can be in the pure form or in the form of an alloy.


$Mineral:$  Minerals are substances that are formed naturally in the earth.  Minerals are usually solid, inorganic, have a crystal structure, and are formed naturally by geological process.


$Gangue:$ It is sand, rock and other impurities surrounding the minerals of interest in an ore. It is the combined state of the metal.

$Flux:$ It is a chemical cleaning, flowing or purifying agent.  It is the substance added to the molten metals to bond with impurities that can be removed.

$Native form:$ Native element, any number of chemical elements that may occur in nature uncombined with other elements.


Hence, the correct option is B.

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

Sulphide ores are common for metals:

  1. Ag, Cu and Pb

  2. Ag, Cu and Sn

  3. Ag, Mg and Pb

  4. none
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  1. Argentite $Ag _2S$
  2.  Galena $PbS$
  3.  Chalcocite $Cu _2S$
  4.  Copper pyrite (chalco pyrite)$ [CuFeS _2]$
  5.  Cassiiterite $SnO _2$
  6.  Dolomite  [$ Ca Mg (CO _3) _2$]
  7.  Bauxite $Al(OH) _3$

∴ Sulphide containing ores are$ Ag, Cu, Pb.$


Option A is correct.