# JEE Main

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## Mathematics

General Principles and Processes of Isolation of Elements

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Q 1. The ores that are concentrated by froth floatation method are:-

A

Carbonates

Sulphides

C

Oxides

D

Phosphates

##### Explanation

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Q 2. The purpose of adding {tex} \mathrm { Na } _ { 3 } \mathrm { AlF } _ { 6 } {/tex} to {tex} \mathrm { Al } _ { 2 } \mathrm { O } _ { 3 } {/tex} during electrolysis is:-

A

To decrease melting point of {tex} \mathrm { Al } _ { 2 } \mathrm { O } _ { 3 } {/tex}

B

To increase conductivity of electrolyte

C

To provide reducing conditions in the bath

Both (a) and (b)

##### Explanation

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Q 3. The method of Zone refining of metals is based on the principle of:

Greater solubility of the impurities in the molten state than in the solid.

B

Greater solubility of pure metal than that of impurity.

C

Higher melting point of the impurity than that of pure metal.

D

Greater noble character of the solid metal than that of the impurity.

##### Explanation

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Q 4. Which of the following is not correctly matched?

A

{tex} \mathrm { ZnCO } _ { 3 } \rightarrow {/tex} Zn (Calcination followed by smelting)

{tex} \mathrm { Al } ( \mathrm { OH } ) _ { 3 } \rightarrow {/tex} Al (Calcination followed by smelting)

C

{tex} \mathrm { PbS } \rightarrow {/tex} Pb (Partial roasting followed by self reduction)

D

{tex} \mathrm { Cu } _ { 2 } \mathrm { S } \rightarrow {/tex} Cu (Complete roasting following by carbon reduction)

##### Explanation

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Q 5. When an impurity in metal has greater affinity for oxygen and is more easily oxidized than metal itself then the metal is refined by:

Cupellation

B

Zone refining

C

Poling

D

Electrolytic process

##### Explanation

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Q 6. What is the appropriate process for the extraction of lead from galena?
(A) Froth floatation (B) Calcination (C) Roasting (D) Self reduction (E) Electrolytic reduction (F) smelting (G) Leaching

A

{tex} \mathrm { G } \rightarrow \mathrm { B } \rightarrow \mathrm { D } \rightarrow \mathrm { E } {/tex}

{tex} A \rightarrow C \rightarrow D {/tex}

C

{tex} \mathrm { A } \rightarrow \mathrm { C } \rightarrow \mathrm { E } {/tex}

D

{tex} \mathrm { A } \rightarrow \mathrm { C } \rightarrow \mathrm { F } {/tex}

##### Explanation

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Q 7. In purification of bauxite ore, it is mixed with coke and heated at {tex} 1800 ^ { \circ } \mathrm { C } {/tex} in presence of nitrogen. This is:

A

Hall's process

Serpeck's process

C

Baeyer's process

D

Electrolytic reduction

##### Explanation

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Q 8. Select the reaction which does not occur in Bessemer's convertor:

A

{tex} \mathrm { FeS } + \mathrm { O } _ { 2 } \rightarrow \mathrm { FeO } + \mathrm { SO } _ { 2 } {/tex}

B

{tex} 2 \mathrm { Cu } _ { 2 } \mathrm { S } + 3 \mathrm { O } _ { 2 } \rightarrow 2 \mathrm { Cu } _ { 2 } \mathrm { O } + 2 \mathrm { SO } _ { 2 } {/tex}

C

{tex} \mathrm { FeO } + \mathrm { SiO } _ { 2 } \rightarrow \mathrm { FeSiO } _ { 3 } {/tex}

{tex} 2 \mathrm { CuFeS } _ { 2 } + \mathrm { O } _ { 2 } \rightarrow \mathrm { Cu } _ { 2 } \mathrm { S } + 2 \mathrm { FeS } + \mathrm { SO } _ { 2 } {/tex}

##### Explanation

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Q 9. Which of the following process is not involved in the extraction of Ag from argentite?

A

Hydrometallurgy

B

Formation of cyanide

Levigation

D

Reduction by Zn metal

##### Explanation

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Q 10. Select the incorrect statement:

A

Based on reactivity series, occurrence of certain elements takes place in native state.

B

Due to the basic nature of oxides of alkaline earth metals, they combine with atmospheric acidic oxides giving salts.

C

Chalcopyrite ore contains both {tex} \mathrm {Cu} {/tex} and {tex} \mathrm {Fe} {/tex} .

Both anglesite and cassiterite contain {tex} \mathrm { Pb } {/tex} .

##### Explanation

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Q 11. Which of the following is not correctly matched?

A

Removal of oxide impurity from impure Cu {tex} \rightarrow {/tex} Poling process

B

Removal of Pb impurity from impure {tex} \mathrm { Ag } \rightarrow {/tex} Cupellation

Obtaining wrought iron from cast iron {tex} \rightarrow {/tex} Bessemerisation

D

Refining of Nickel {tex} \rightarrow {/tex} Mond's process

##### Explanation

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Q 12. Which of the following statement is not correct?

Tin stone is speratated from non-magnetic impurity of wolframite by electrolytic separation.

B

CO acts as reducing agent is most parts of blast furnace during extraction of iron.

C

A silicate slag is obtained during the extraction of Cu from CuFeS, and iron from haematite.

D

In Puddling process, impurities present in cast iron are oxidized by haematite.

##### Explanation

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Q 13. Three most occurring elements into the earth crust are:

{tex} \mathrm { O } , \mathrm { Si } , \mathrm { Al } {/tex}

B

{tex}\mathrm{Si}, \mathrm { O } , \mathrm { Fe } {/tex}

C

{tex} \mathrm { Fe } , \mathrm { Ca } , \mathrm { Al } {/tex}

D

{tex} \mathrm { Si } , \mathrm { O } , \mathrm { N } {/tex}

##### Explanation

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Q 14. An example of an oxide ore is

Bauxite

B

Malachite

C

Zinc blende

D

Feldspar

##### Explanation

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Q 15. Which of the following set of elements mostly occur as sulphide ores?

A

{tex} \mathrm { Zn } , \mathrm { Cu } , \mathrm { Na } {/tex}

{tex} \mathrm { Zn } , \mathrm { Cu } , \mathrm { Pb } {/tex}

C

{tex} \mathrm { Fe } , \mathrm { Al } , \mathrm { Ti } {/tex}

D

{tex} \mathrm { Cu } , \mathrm { Ag } , \mathrm { Au } {/tex}

##### Explanation

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Q 16. Slag is formed by reaction between:

A

Impurities and coke

B

Impurities and ore

Impurities and flux

D

Flux and coke

##### Explanation

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Q 17. Which one of following beneficiation processes is used for the mineral {tex} \mathrm { Al } _ { 2 } \mathrm { O } _ { 3 } \cdot 2 \mathrm { H } _ { 2 } \mathrm { O } {/tex} ?

A

Froth floatation

Leaching

C

Liquation

D

Magnetic separation

##### Explanation

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Q 18. Cassiterite is concentrated by:

A

Levigation

Electromagnetic separation

C

Froth-floatation

D

Liquification

##### Explanation

Cassiterite or tin stone (SnO2​) is non-magnetic and found associated with magnetic impurities. Thus, it is concentrated by electromagnetic separation.

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Q 19. Gravity separation process may be used for the concentration of:

A

Chalcopyrite

B

Bauxite

Haematite

D

Calamine

##### Explanation

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Q 20. Bauxite is leached with:

A

{tex} \mathrm { KCN } {/tex}

B

{tex} \mathrm { NaCN } {/tex}

{tex} \mathrm { NaOH } {/tex}

D

{tex} \mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 } {/tex}