Tag: occurrence of metals

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Questions Related to occurrence of metals

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

Pyrolusite is:

  1. a sulphide ore of $Mn$
  2. an oxide ore of $Mn$
  3. a carbide ore of $P$
  4. a chloride ore of $Zn$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Out of many minerals in which a metal may be found, only a few are viable to be used as source of that metal. Such minerals are known as ores.
Not all elements exists in pure states. Some elements exist in combined states.Among them the viable ones are there ores and the pure metal is obtained after undergoing various metallurgical processes.
Pyrolusite-($MnO _2$) is an oxide ore of Manganese.

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

Magnesium oxide is used for the lining in steel making furnace because:

  1. $MgO$ acts as an acidic flux to remove impurities of $Si,\ P$ and $S$
  2. $MgO$ acts as a basic flux to remove impurities of $Si,\ P$ and $S$
  3. $MgO$ acts as an oxidising agent to remove impurities of oxides
  4. $MgO$ does not react with any type of impurities
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The impurities of the furnace are acidic. So to remove them, basic fluxes are added to remove it as slag.


Example: $MgO+SiO _2\rightarrow MgSiO _3$
                                                 slag

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

During the formation of the slag by the reaction of flux and impurities which of the following is an example of acidic and basic flux?
(i) $FeO + SiO _2\rightarrow FeSiO _3$
(ii) $SiO _2+MgO\rightarrow MgO\rightarrow MgSiO _3$

  1. (i) $SiO _2$ - Acidic flux (ii) $MgO$ - Basic flux
  2. (i) $SiO _2$ - Basic flux (ii) $MgO$ - Acidic flux
  3. (i) $SiO _2$ - Basic flux (ii) $MgO$ - Basic flux
  4. (i)$ SiO _2$ - Acidic flux (ii) $MgO$ - Acidic flux
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
i) $FeO+Si{ O } _{ 2 }\longrightarrow FeSi{ O } _{ 3 }$
In it $Si{ O } _{ 2 }$ is acidic flux and used to remove basic impurities.
ii) $Si{ O } _{ 2 }+MgO\longrightarrow MgSi{ O } _{ 3 }$
$Si{ O } _{ 2 }$ is acidic impurity. $MgO$ is basic flux used to remove $MgSi{ O } _{ 3 }$ as slag.
Multiple choice geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

Impurities of sulphur, silicon, and phosphorus can be removed from cast iron by adding:

  1. carbon which reduces the impurities

  2. water which dissolves the impurities

  3. limestone which changes impurities into oxides and pass into slag

  4. iron oxide which reacts with impurities by forming slag
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Flux is added to remove impurities as slag. So impurities like Sulphur, Silicon and Phosphorous are removed from case Iron by adding flux. Here flux is $CaC{ O } _{ 3 }$

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

In the extraction of some metals from their ores, coke can be used as:

  1. Oxidizing agent

  2. Reducing agent

  3. Catalyst

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

Metals below carbon in the reactivity series can be extracted using carbon. Carbon reduces the metal oxides that are extracted when heated. 


For example, the common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. 

Hence, option B is correct.