Tag: study of kerala

Questions Related to study of kerala

Pyrolusite is:

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

  1. a sulphide ore of $Mn$

  2. an oxide ore of $Mn$

  3. a carbide ore of $P$

  4. a chloride ore of $Zn$

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Correct Option: B
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.

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

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

  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

Show answer
Correct Option: B
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

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) $SiO _2+MgO\rightarrow MgO\rightarrow MgSiO _3$

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

  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

Show answer
Correct Option: A
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.

A number of elements are available in earth's crust but most abundant elements are _______.

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

  1. $Al$ and $Fe$

  2. $Fe$ and $Cu$

  3. $Cu$ and $Ag$

  4. none of these

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Correct Option: A
Explanation:

Aluminium is the first most abundant metal element and Iron is the next element.

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

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

  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

Show answer
Correct Option: C
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 $CaC{ O } _{ 3 }$

Sulphur molecule exists as :

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

  1. $S _2$

  2. $S$

  3. $S _6$

  4. $S _8$

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Correct Option: D
Explanation:

Sulphur molecule exists as $S _8$.

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

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

  1. Oxidizing agent

  2. Reducing agent

  3. Catalyst

  4. Flux

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Correct Option: B
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.

If an ore contains impurity of $SiO _2$, identify the appropriate flux for the removal of it:

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

  1. $MnO$

  2. $P _4O _{10}$

  3. $CO _2$

  4. $SO _2$

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Correct Option: A
Explanation:

$MnO + SiO _2 \rightarrow MnSiO _3(Slag)$

Electrolytic reduction method is used for extraction?

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

  1. Highly electronegative elements

  2. Transition metals

  3. Highly electropositive elements

  4. Metalloids

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Correct Option: C
Explanation:

Electrolytic reduction method is used for entraction of highly electropositive elements.

Example: $Na,K,Mg,Ca$ are obtained by electrolytic reduction processes.

In metallurgy, reduction is one of the major steps. However, all ores may not require an extra reducing agent, one such metallurgical operation is the extraction of?

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

  1. Fe from magnetite

  2. Sn from cassiterite

  3. Hg from cinnabar

  4. Zn from zinc blende

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Correct Option: D