When copper pyrites is roasted in excess if air, a mixture of ${\rm{CuO}} + {\rm{FeO}}$ is formed .${\rm{FeO}}$ is present as impurities. This can be removed as slag during reduction of ${\rm{CuO}}$. The flux added to from slag is

${\rm{Si}}{{\rm{O}}_2}\;\;$ which is an acid flux

Lime stone, which is a basic flux

${\rm{Si}}{{\rm{O}}_2}\;\;$,which is basic flux

Consider two chemical reactions $(A)$ and $(B)$ that take place during metallurgical process: $(A)$ ${\rm{ZnC}}{{\rm{O}}_{\rm{3}}}{\rm{(s)}}\xrightarrow{{\rm{\Delta }}}{\rm{ZnO (s) + C}}{{\rm{o}}_{\rm{2}}}{\rm{(g)}}$ $(B)$ ${\rm{2ZnS (s) + 3}}{{\rm{O}}_{\rm{2}}}{\rm{(g)}}\xrightarrow{{\rm{\Delta }}}{\rm{2ZnO (s) + 2S}}{{\rm{O}}_{\rm{2}}}{\rm{(g)}}$ The correct option of names given to them respectively is

Both $(A)$ and $(B)$ are producing same product so both are roasting

Both $(A)$ and $(B)$ are producing same product so both are calcination

$(A)$ is roasting and $(B)$ is calcination

GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS MCQs for NEET UG CHEMISTRY — Easy

1 Easy

1 of 69Question permalink

Understanding +4 | -1

In the extraction of copper, the metal formed in the Bessemer’s converter is due to the reaction:

View answer and explanation

Correct option: D

2\mathrm{C}{\mathrm{u}_2}\mathrm{O} + \mathrm{C}{\mathrm{u}_2}\mathrm{S} \to 6\mathrm{Cu} + \mathrm{S}{\mathrm{O}_2}

Option D (

2\mathrm{C}{\mathrm{u}_2}\mathrm{O} + \mathrm{C}{\mathrm{u}_2}\mathrm{S} \to 6\mathrm{Cu} + \mathrm{S}{\mathrm{O}_2}

) is correct because this reaction represents the self-reduction of cuprous oxide by cuprous sulfide in the Bessemer converter to produce copper.

Solution approach

Correct Answer + Core Reason: $2Cu_2O + Cu_2S \rightarrow 6Cu + SO_2$ is the reaction in Bessemer's converter.

Step-by-Step Solution:

Step 1: Recall the reactions in the extraction of copper.

Step 2: In the Bessemer converter, $Cu_2O$ reacts with $Cu_2S$ to produce copper and $SO_2$ .

Step 3: $2Cu_2O + Cu_2S \rightarrow 6Cu + SO_2$

Why other options are wrong:
- Option A: $Cu_2S \rightarrow 2Cu + S$ is not the primary reaction in the Bessemer converter.
- Option B: $2Cu_2O \rightarrow 4Cu + O_2$ is not the primary reaction in the Bessemer converter.
- Option C: $2Cu_2S + 3O_2 \rightarrow 2Cu_2O + 2SO_2$ is the roasting process, not the final step in the Bessemer converter.

Key Concepts:
- Copper extraction
- Bessemer converter
- Self-reduction

Memory Aids:
- Remember the balanced equation for the final step.

Quick Tips:
- Understand the sequence of reactions in copper extraction.

2 Easy

2 of 69Question permalink

Understanding +4 | -1

Leaching is a process of:

View answer and explanation

Correct option: B

Concentration

Option B (Concentration) is correct because leaching is a method used to selectively dissolve the desired ore, thus concentrating it.

Solution approach

Correct Answer + Core Reason: Concentration. Leaching selectively dissolves the desired ore, leaving impurities behind.

Step-by-Step Solution:

Step 1: Define leaching. Leaching is a process where a solid material is dissolved in a liquid solvent to extract the desired component.

Step 2: Explain its application in metallurgy. In metallurgy, leaching is used to selectively dissolve the ore, leaving behind the gangue (impurities).

Step 3: Examples of leaching agents. Common leaching agents include acids, bases, and cyanide solutions.

Why other options are wrong:
- Option A: Reduction. Reduction is a chemical process where a substance gains electrons. While reduction can occur during metal extraction, leaching itself is primarily a separation technique, not a reduction process.
- Option C: Refining. Refining is the process of purifying a metal after it has been extracted from its ore. Leaching occurs before refining.
- Option D: Oxidation. Oxidation is a chemical process where a substance loses electrons. While oxidation can be involved in some leaching processes, the primary purpose of leaching is concentration, not oxidation.

Key Concepts:
- Leaching
- Concentration
- Solvent Extraction

Memory Aids:
- Leaching: \"Leech\" - to extract something by dissolving it.

Quick Tips:
- Remember that leaching is a method for selectively dissolving the desired ore, thus concentrating it.

3 Easy

3 of 69Question permalink

Understanding +4 | -1

In the extraction of copper metal is formed in the Bessemer converter due to reaction

View answer and explanation

Correct option: A

C{u_2}S + 2C{u_2}O \to 6Cu + S{O_2}

Option A (

Cu_2S + 2Cu_2O \to 6Cu + SO_2

) is correct because this reaction represents the self-reduction of copper oxides and sulfides in the Bessemer converter.

Solution approach

Correct Answer + Core Reason: $Cu_2S + 2Cu_2O \to 6Cu + SO_2$ . This reaction represents the final step in copper extraction in the Bessemer converter.

Step-by-Step Solution:

Step 1: In the Bessemer converter, the matte (mainly $Cu_2S$ and $FeS$ ) is treated with silica lining and hot air.

Step 2: The iron sulfide is oxidized to iron oxide, which then reacts with silica to form slag.

Step 3: The remaining copper sulfide is partially oxidized to copper oxide, which then reacts with the remaining copper sulfide to form copper metal and sulfur dioxide.

Step 4: The reaction is: $Cu_2S + 2Cu_2O \rightarrow 6Cu + SO_2$

Why other options are wrong:
- Option B: $Cu_2S \to 2Cu + S$ is not the primary reaction in the Bessemer converter.
- Option C: $Fe + Cu_2O \to FeO + 2Cu$ is not the main reaction occurring in the Bessemer converter.
- Option D: $2Cu_2O \to 4Cu + O_2$ is not the primary reaction in the Bessemer converter.

Key Concepts:
- Metallurgy of Copper
- Bessemerization
- Self-reduction

Memory Aids:
- Remember the self-reduction of copper sulfide and oxide to form copper metal.

Quick Tips:
- The Bessemer converter is used for the final reduction of copper.

4 Easy

4 of 69Question permalink

Remembering +4 | -1

Vapour phase refining of nickel is carried out by using

View answer and explanation

Correct option: D

\mathrm{CO}

Option D (CO) is correct because carbon monoxide (CO) is used in the Mond process for vapor phase refining of nickel.

Solution approach

Correct Answer + Core Reason: CO. Carbon monoxide is used in the Mond process for refining nickel.

Step-by-Step Solution:

Step 1: Recall the Mond process: The Mond process involves reacting impure nickel with carbon monoxide (CO) to form volatile nickel tetracarbonyl ( $Ni(CO)_4$ ).

Step 2: The nickel tetracarbonyl is then heated to decompose it, yielding pure nickel and carbon monoxide, which can be recycled.

Step 3: The reaction is: $Ni + 4CO \rightleftharpoons Ni(CO)_4$

Why other options are wrong:
- Option A: $I_2$ is used in the Van Arkel method for refining Zr and Ti, not Ni.
- Option B: $Cl_2$ is not typically used in vapor phase refining of Ni.
- Option C: $HCl$ is not typically used in vapor phase refining of Ni.

Key Concepts:
- Mond Process
- Vapor Phase Refining
- Nickel Tetracarbonyl ( $Ni(CO)_4$ )

Memory Aids:
- Mond: Ni + CO -> $Ni(CO)_4$ -> Pure Ni

Quick Tips:
- Remember the reactants and products in the Mond process.
- Understand the purpose of forming a volatile compound in vapor phase refining.

5 Easy

5 of 69Question permalink

Understanding +4 | -1

Metallurgy is the process of:

View answer and explanation

Correct option: C

Extracting the metal from the ore

Option C (Extracting the metal from the ore) is correct because metallurgy is the science and technology of extracting metals from their ores.

Solution approach

Correct Answer + Core Reason: Extracting the metal from the ore. Metallurgy is the process of extracting metals.

Step-by-Step Solution:
Step 1: Define Metallurgy.
Step 2: Metallurgy is the process of extracting metals from their ores and refining them for use.

Why other options are wrong:
- Option A: Concentrating the ore is a part of metallurgy, but not the entire process.
- Option B: Roasting the ore is a part of metallurgy, but not the entire process.
- Option D: Adding carbon to the ore in a blast furnace is a specific step in iron extraction, not the definition of metallurgy itself.

Key Concepts:
- Metallurgy
- Metal extraction

Memory Aids:
- Metallurgy involves extracting metals.

Quick Tips:
- Understand the different processes involved in metallurgy.

6 Easy

6 of 69Question permalink

Remembering +4 | -1

Which one is malachite from the following?

View answer and explanation

Correct option: D

CuC{O_3}.\,Cu{(OH)_2}

Option D (

CuCO_3.\,Cu(OH)_2

) is correct because it represents the chemical formula of malachite, a copper carbonate hydroxide mineral.

Solution approach

Correct Answer + Core Reason: $CuCO_3.\,Cu(OH)_2$ is the chemical formula for malachite.

Step-by-Step Solution:

Step 1: Recall the definition of malachite.

Step 2: Malachite is a copper carbonate hydroxide mineral.

Step 3: Identify the chemical formula that corresponds to copper carbonate hydroxide.

Step 4: The chemical formula for malachite is $CuCO_3.\,Cu(OH)_2$ .

Why other options are wrong:
- Option A: $CuFeS_2$ is the chemical formula for chalcopyrite, a copper iron sulfide mineral.
- Option B: $Cu(OH)_2$ is the chemical formula for copper(II) hydroxide, but malachite also contains carbonate.
- Option C: $Fe_3O_4$ is the chemical formula for magnetite, an iron oxide mineral.

Key Concepts:
- Mineral identification
- Chemical formulas of minerals

Memory Aids:
- None applicable

Quick Tips:
- Memorize common mineral formulas.

7 Easy

7 of 69Question permalink

Remembering +4 | -1

Which of the following is correct?

View answer and explanation

Correct option: C

Calomel is used medically as purgative

Option C is correct because calomel (Hg2Cl2) is used medically as a purgative (laxative).

Solution approach

Correct Answer + Core Reason: Calomel is used medically as purgative. Calomel (Hg2Cl2) has been used as a purgative.

Step-by-Step Solution:

Step 1: Recall the properties and uses of calomel.

Step 2: Calomel (Hg2Cl2) is mercurous chloride, not mercuric chloride.
- It has been used medically as a purgative.
- It is not freely soluble in water.
- It is not widely used as an antiseptic.

Why other options are wrong:
- Option A: Calomel is mercurous chloride (Hg2Cl2), not mercuric chloride (HgCl2).
- Option B: Calomel is not widely used as an antiseptic.
- Option D: Calomel is not freely soluble in water.

Key Concepts:
- Properties and uses of calomel

Memory Aids:
- Calomel: Remember its use as a purgative.

Quick Tips:
- Know the different forms of mercury chlorides and their uses.

8 Easy

8 of 69Question permalink

Understanding +4 | -1

Which method of purification is represented by the following equations

Ti + 2{I_2}\xrightarrow{{523\,K}}Ti{I_4}\xrightarrow{{1700\,K}}Ti + 2{I_2}

View answer and explanation

Correct option: C

Van Arkle

Option C (Van Arkle) is correct because the given equations represent the Van Arkel method, which involves forming a volatile iodide to purify metals.

Solution approach

Correct Answer + Core Reason: Van Arkle. The given reaction is the Van Arkel method for refining metals like Titanium.

Step-by-Step Solution:

Step 1: The Van Arkel method involves converting the impure metal to a volatile iodide at a lower temperature.

Step 2: The volatile iodide is then decomposed at a higher temperature to yield the pure metal.

Step 3: The reactions are: $Ti + 2I_2 \xrightarrow{{523 K}} TiI_4$ and $TiI_4 \xrightarrow{{1700 K}} Ti + 2I_2$

Why other options are wrong:
- Option A: Cupellation is used for refining precious metals like silver and gold.
- Option B: Poling is used for refining copper and involves stirring molten metal with green wood.
- Option D: Zone refining is based on the principle that impurities are more soluble in the molten phase than in the solid phase.

Key Concepts:
- Refining of metals
- Van Arkel method

Memory Aids:
- Van Arkel uses Iodine to purify metals like Ti and Zr.

Quick Tips:
- Remember the specific refining methods for different metals.

9 Easy

9 of 69Question permalink

Remembering +4 | -1

Composition of azurite mineral is

View answer and explanation

Correct option: C

2\mathrm{CuC}{\mathrm{O}_3}.\mathrm{Cu}{\left( {\mathrm{OH}} \right)_2}

Option C is correct because the chemical formula for azurite is

2\mathrm{CuC}{\mathrm{O}_3}.\mathrm{Cu}{\left( {\mathrm{OH}} \right)_2}

.

Solution approach

Correct Answer + Core Reason: $2\mathrm{CuC}{\mathrm{O}_3}.\mathrm{Cu}{\left( {\mathrm{OH}} \right)_2}$ . This is the correct chemical formula for azurite.

Step-by-Step Solution:

Step 1: Recall the chemical formula of azurite.

Step 2: Azurite is a copper carbonate hydroxide mineral with the formula $2\mathrm{CuC}{\mathrm{O}_3}.\mathrm{Cu}{\left( {\mathrm{OH}} \right)_2}$ .

Why other options are wrong:
- Option A: Incorrect formula.
- Option B: Incorrect formula.
- Option D: Incorrect formula.

Key Concepts:
- Mineral formulas
- Chemical composition of azurite

Memory Aids:
- Azurite: Remember the copper carbonate hydroxide formula.

Quick Tips:
- Memorize the formulas of common minerals.

10 Easy

10 of 69Question permalink

Remembering +4 | -1

Which of the following pairs of metal is purified by zone refining method ?

View answer and explanation

Correct option: D

Si and Ge

Option D is correct because Silicon (Si) and Germanium (Ge) are semiconductors that are commonly purified using the zone refining method.

Solution approach

Correct Answer + Core Reason: Si and Ge. Zone refining is commonly used to purify semiconductors like Si and Ge.

Step-by-Step Solution:

Step 1: Understand the principle of zone refining.
- Zone refining is a method for purifying materials by melting a small region (zone) and moving it along the material.
- Impurities tend to concentrate in the molten zone.

Step 2: Identify the metals that are commonly purified by zone refining.
- Silicon (Si) and Germanium (Ge) are semiconductors that require high purity for their applications.

Why other options are wrong:
- Option A: Ga and Ni are not typically purified by zone refining.
- Option B: Zr and Ti can be purified by Van Arkel method.
- Option C: Ag and Au are purified by other methods like electrolytic refining.

Key Concepts:
- Zone refining
- Purification of semiconductors

Memory Aids:
- Zone refining: Think of semiconductors (Si, Ge).

Quick Tips:
- Remember the materials that require high purity and the methods used to achieve it.

11 Easy

11 of 69Question permalink

Understanding +4 | -1

In the manufacture of iron from haematite, lime stone is added to act as:

View answer and explanation

Correct option: A

Flux

Option A (Flux) is correct because limestone acts as a flux to remove silica impurities in the form of slag during iron production.

Solution approach

Correct Answer + Core Reason: Flux. Limestone acts as a flux to remove silica impurities.

Step-by-Step Solution:
Step 1: Understand the role of limestone in the extraction of iron.
Step 2: Limestone ( $\mathrm{CaCO}_3$ ) decomposes to calcium oxide (CaO) which acts as a basic flux. It reacts with silica ( $\mathrm{SiO}_2$ ), an acidic impurity, to form slag ( $\mathrm{CaSiO}_3$ ).

Why other options are wrong:
- Option B: Slag is the product formed by the reaction of the flux with impurities, not the role of limestone itself.
- Option C: A reducing agent reduces the iron oxide to iron, but limestone is not a reducing agent.
- Option D: An oxidising agent oxidises other substances, but limestone is not an oxidising agent.

Key Concepts:
- Extraction of iron
- Flux and slag

Memory Aids:
- Limestone acts as a flux.

Quick Tips:
- Remember the roles of different substances in metallurgical processes.

12 Easy

12 of 69Question permalink

Remembering +4 | -1

Gold is extracted using:

View answer and explanation

Correct option: A

Amalgamation process

Option A (Amalgamation process) is correct because gold is often extracted using the amalgamation process, where it forms an amalgam with mercury.

Solution approach

Correct Answer + Core Reason: Amalgamation process. Gold forms an amalgam with mercury, which is then separated.

Step-by-Step Solution:

Step 1: Identify the element: The question is about the extraction of gold.

Step 2: Recall the extraction methods: The amalgamation process is a method used to extract gold from its ore. It involves using mercury to form an amalgam with the gold.

Step 3: Conclusion: Therefore, the answer is the amalgamation process.

Why other options are wrong:
- Option B: Carbon reduction is used for extracting metals like iron, not gold.
- Option C: Oxidation process is a general term and not specific to gold extraction in the way amalgamation is.
- Option D: Electrolytic process is used for refining metals like copper and aluminum, and can be used for gold refining, but it's not the primary extraction method from ore.

Key Concepts:
- Metallurgy
- Gold extraction
- Amalgamation

Memory Aids:
- Think of \"amalgam\" as a mixture of gold and mercury.

Quick Tips:
- Remember that amalgamation is a specific process used for gold extraction.

13 Easy

13 of 69Question permalink

Understanding +4 | -1

Identify the correct statement from the following:

View answer and explanation

Correct option: D

Pig iron can be moulded into a variety of shapes.

Option D (Pig iron can be moulded into a variety of shapes) is correct because pig iron has a high carbon content, making it easily moldable.

Solution approach

Correct Answer + Core Reason: Pig iron can be moulded into a variety of shapes. Pig iron has a high carbon content which makes it easily moldable.

Step-by-Step Solution:

Step 1: Wrought iron is actually a very pure form of iron with a low carbon content (typically less than 0.08%), not an impure form with 4% carbon.

Step 2: Blister copper's blistered appearance is due to the evolution of $SO_2$ , not $CO_2$ .

Step 3: Vapour phase refining for Nickel is done by Mond's process, not Van Arkel method. Van Arkel is used for metals like Zirconium and Titanium.

Step 4: Pig iron, with its high carbon content, is indeed easily cast into various shapes, although it is brittle.

Why other options are wrong:
- Option A: Wrought iron is very pure iron, not impure with 4% carbon.
- Option B: Blister copper's blisters are due to $SO_2$ evolution, not $CO_2$ .
- Option C: Van Arkel method is for Titanium and Zirconium, not Nickel. Mond's process is for Nickel.

Key Concepts:
- Metallurgy of Iron and Copper
- Refining methods

Memory Aids:
- Mond's process for Nickel, Van Arkel for Ti/Zr.

Quick Tips:
- Remember the specific refining methods for different metals and the composition of different types of iron.

14 Easy

14 of 69Question permalink

Remembering +4 | -1

The metal which is not purified by vapour phase refining is

View answer and explanation

Correct option: B

Zn

Option B (Zn) is correct because Zinc is purified by distillation, not vapor phase refining.

Solution approach

Correct Answer + Core Reason: Zn. Zinc is purified by distillation, not vapor phase refining.

Step-by-Step Solution:

Step 1: Define vapor phase refining: Vapor phase refining involves converting a metal to a volatile compound, separating it from impurities, and then decomposing the volatile compound to obtain the pure metal.

Step 2: Consider Ni: Nickel is purified by Mond's process, a vapor phase refining method where Ni reacts with CO to form $Ni(CO)_4$ , which is then decomposed to yield pure Ni.

Step 3: Consider Zr and Ti: Zirconium and Titanium are purified by the Van Arkel method, another vapor phase refining technique where they react with iodine to form volatile iodides, which are then decomposed.

Step 4: Consider Zn: Zinc is typically purified by distillation or electrolytic refining, not vapor phase refining.

Why other options are wrong:
- Option A: Ni is purified by Mond's process (vapor phase refining).
- Option C: Zr is purified by the Van Arkel method (vapor phase refining).
- Option D: Ti is purified by the Van Arkel method (vapor phase refining).

Key Concepts:
- Vapor Phase Refining
- Mond's Process (for Ni)
- Van Arkel Method (for Zr and Ti)
- Distillation

Memory Aids:
- Mond: Ni + CO -> $Ni(CO)_4$ -> Pure Ni
- Van Arkel: Zr/Ti + $I_2$ -> Volatile Iodide -> Pure Zr/Ti

Quick Tips:
- Remember the specific metals purified by each refining method.
- Know the volatile compounds formed in vapor phase refining.

15 Easy

15 of 69Question permalink

Remembering +4 | -1

Which of the following ore is an ore of copper?

View answer and explanation

Correct option: C

Malachite

Option C is correct because Malachite is a copper carbonate hydroxide mineral and is a well-known ore of copper.

Solution approach

Correct Answer + Core Reason: Malachite. Malachite is a copper carbonate hydroxide mineral, $CuCO_3.Cu(OH)_2$ , and is an ore of copper.

Step-by-Step Solution:

Step 1: Recall the common ores of copper.

Step 2: Malachite is a well-known ore of copper.

Step 3: Compare the given options with the known ores of copper.

Why other options are wrong:
- Option A: Argentite ( $Ag_2S$ ) is an ore of silver.
- Option B: Haematite ( $Fe_2O_3$ ) is an ore of iron.
- Option D: Calamine ( $ZnCO_3$ ) is an ore of zinc.

Key Concepts:
- Ores of metals
- Copper ores

Memory Aids:
- Malachite is green and contains copper.

Quick Tips:
- Memorize the common ore formulas.

16 Easy

16 of 69Question permalink

Understanding +4 | -1

Work is being performed, when a weight lifter lifts a base ball off a weight rack. This is due to

View answer and explanation

Correct option: B

Gravity

Option B (Gravity) is correct because the weightlifter is working against the force of gravity when lifting the baseball.

Solution approach

Correct Answer + Core Reason: Gravity. The weightlifter is working against the force of gravity.

Step-by-Step Solution:

Step 1: Define work. Work is done when a force causes displacement.

Step 2: Identify the forces acting on the baseball. The primary force acting on the baseball is gravity, pulling it downwards.

Step 3: The weightlifter applies an upward force to counteract gravity and lift the baseball.

Step 4: Since the weightlifter is applying a force against gravity to lift the baseball, the work is being performed due to gravity.

Why other options are wrong:
- Option A: Magnetic attraction is not relevant in this scenario as baseballs are not significantly magnetic.
- Option C: Electrostatic repulsion is not the primary force involved in lifting a baseball.
- Option D: Mechanical force is a general term, but the specific force being overcome is gravity.

Key Concepts:
- Work: Force x Distance
- Gravity: The force that attracts objects with mass towards each other.

Memory Aids:
- Work is done against a force. In this case, the force is gravity.

Quick Tips:
- Identify the forces involved in the action to determine the reason for work being performed.

17 Easy

17 of 69Question permalink

Understanding +4 | -1

When copper pyrites is roasted in excess if air, a mixture of

\mathrm{CuO} + \mathrm{FeO}

is formed .

\mathrm{FeO}

is present as impurities. This can be removed as slag during reduction of

\mathrm{CuO}

. The flux added to from slag is

View answer and explanation

Correct option: A

\mathrm{Si}{\mathrm{O}_2}\;\;

which is an acid flux

Option A (

\mathrm{Si}{\mathrm{O}_2}

which is an acid flux) is correct because it reacts with the basic

\mathrm{FeO}

impurity to form slag.

Solution approach

Correct Answer + Core Reason: $\mathrm{Si}{\mathrm{O}_2}$ which is an acid flux. Acidic flux is used to remove basic impurities like FeO.

Step-by-Step Solution:

Step 1: Identify the impurity. The impurity is $\mathrm{FeO}$ , which is a basic oxide.

Step 2: Determine the type of flux needed. To remove a basic impurity, an acidic flux is required.

Step 3: Identify the acidic flux among the options. $\mathrm{Si}{\mathrm{O}_2}$ is an acidic flux.

Step 4: The reaction between the acidic flux and the basic impurity forms a slag, which can be easily removed.
$\mathrm{FeO} + \mathrm{SiO}_2 \rightarrow \mathrm{FeSiO}_3$ (Slag)

Why other options are wrong:
- Option B: Limestone ( $\mathrm{CaCO}_3$ ) is a basic flux and is used to remove acidic impurities, not basic impurities like $\mathrm{FeO}$ .
- Option C: $\mathrm{Si}{\mathrm{O}_2}$ is an acidic flux, not a basic flux. This option incorrectly identifies it as basic.
- Option D: CaO is a basic flux and is used to remove acidic impurities, not basic impurities like $\mathrm{FeO}$ .

Key Concepts:
- Metallurgy
- Flux (Acidic and Basic)
- Slag Formation
- Types of Impurities

Memory Aids:
- Acidic flux removes basic impurities, and basic flux removes acidic impurities.

Quick Tips:
- Remember that acidic oxides react with basic oxides to form salts (slag).

18 Easy

18 of 69Question permalink

Remembering +4 | -1

The grey cast iron contains:

View answer and explanation

Correct option: D

Graphite

Option D (Graphite) is correct because the grey color of grey cast iron is due to the presence of free graphite flakes within the iron matrix.

Solution approach

Correct Answer + Core Reason: Graphite. The grey color in grey cast iron is due to the presence of graphite.

Step-by-Step Solution:

Step 1: Recall the composition of grey cast iron: Grey cast iron contains a significant amount of carbon, which precipitates out as graphite flakes during solidification.

Step 2: Relate the graphite to the color: The presence of these graphite flakes gives the cast iron its characteristic grey color.

Step 3: Evaluate the other options: Iron carbide, silicon carbide, and silicon dioxide are not responsible for the grey color.

Step 4: Conclusion: Graphite is the correct answer.

Why other options are wrong:
- Option A (Iron carbide): Iron carbide (cementite) is a hard and brittle component, but it doesn't directly cause the grey color.
- Option B (Silicon carbide): Silicon carbide is an abrasive material and not the primary cause of the grey color in cast iron.
- Option C (Silicon dioxide): Silicon dioxide is a component of slag and not responsible for the grey color of cast iron.

Key Concepts:
- Metallurgy
- Cast iron
- Composition of cast iron

Memory Aids:
- Grey cast iron = Graphite

Quick Tips:
- Remember that the form of carbon (graphite or iron carbide) significantly affects the properties of cast iron.

19 Easy

19 of 69Question permalink

Remembering +4 | -1

Siderite is an ore of

View answer and explanation

Correct option: D

Fe

Option D (Fe) is correct because siderite is a mineral composed of iron(II) carbonate (

FeCO_3

), making it an ore of iron.

Solution approach

Correct Answer + Core Reason: Siderite ( $FeCO_3$ ) is an ore of iron (Fe).

Step-by-Step Solution:

Step 1: Recall the chemical formula of Siderite.

Step 2: Siderite is $FeCO_3$ , which contains iron (Fe).

Step 3: Therefore, Siderite is an ore of Fe.

Why other options are wrong:
- Option A: Cu (Copper) is extracted from ores like Chalcopyrite.
- Option B: Al (Aluminum) is extracted from Bauxite.
- Option C: Ag (Silver) is extracted from Argentite.

Key Concepts:
- Ores of metals
- Chemical formulas of minerals

Memory Aids:
- Siderite sounds like "iron-side", helping you remember it's an iron ore.

Quick Tips:
- Learn the common ores for important metals.

20 Easy

20 of 69Question permalink

Remembering +4 | -1

On the extraction of iron, the slag produced is

View answer and explanation

Correct option: D

\mathrm{CaSi}{\mathrm{O}_3}

Option D is correct because during iron extraction, calcium silicate (CaSiO3) is formed as slag, which removes impurities from the molten iron.

Solution approach

Correct Answer + Core Reason: $\mathrm{CaSi}{\mathrm{O}_3}$ . Calcium silicate is the slag produced during iron extraction.

Step-by-Step Solution:

Step 1: Understand the process of iron extraction.

Step 2: In the blast furnace, limestone (CaCO3) decomposes to CaO, which then reacts with silica (SiO2) to form slag:
$\mathrm{CaCO_3} \rightarrow \mathrm{CaO} + \mathrm{CO_2}$
$\mathrm{CaO} + \mathrm{SiO_2} \rightarrow \mathrm{CaSiO_3}$

Step 3: Identify the slag formed.

Why other options are wrong:
- Option A: CO is a gas produced during the process, not the slag.
- Option B: $\mathrm{FeSi}{\mathrm{O}_3}$ is not the primary slag formed.
- Option C: $\mathrm{MgSi}{\mathrm{O}_3}$ is not the slag formed.

Key Concepts:
- Iron extraction
- Slag formation

Memory Aids:
- Calcium silicate slag in iron extraction.

Quick Tips:
- Remember the reactions occurring in the blast furnace.

21 Easy

21 of 69Question permalink

Understanding +4 | -1

Consider two chemical reactions

(A)

and

(B)

that take place during metallurgical process:

(A)

\mathrm{ZnC}{\mathrm{O}_\mathrm{3}}\mathrm{(s)}\xrightarrow{\mathrm{\Delta }}\mathrm{ZnO (s) + C}{\mathrm{o}_\mathrm{2}}\mathrm{(g)}

(B)

\mathrm{2ZnS (s) + 3}{\mathrm{O}_\mathrm{2}}\mathrm{(g)}\xrightarrow{\mathrm{\Delta }}\mathrm{2ZnO (s) + 2S}{\mathrm{O}_\mathrm{2}}\mathrm{(g)}

The correct option of names given to them respectively is

View answer and explanation

Correct option: A

(A)

is calcination and

(B)

is roasting

Option A ((A) is calcination and (B) is roasting) is correct because reaction (A) involves heating a carbonate in the absence of air, while reaction (B) involves heating a sulfide in the presence of air.

Solution approach

Correct Answer + Core Reason: (A) is calcination and (B) is roasting. Calcination involves heating a carbonate ore in the absence of air, while roasting involves heating a sulfide ore in the presence of air.

Step-by-Step Solution:

Step 1: Define calcination and roasting.\nCalcination: Heating a carbonate ore in the absence of air to decompose it into its oxide.\nRoasting: Heating a sulfide ore in the presence of air to convert it to an oxide.

Step 2: Analyze reaction (A): $\mathrm{ZnC}{\mathrm{O}_\mathrm{3}}\mathrm{(s)}\xrightarrow{\mathrm{\Delta }}\mathrm{ZnO (s) + C}{\mathrm{o}_\mathrm{2}}\mathrm{(g)}$ \nThis reaction involves heating zinc carbonate, which is a carbonate ore, and it decomposes into zinc oxide and carbon dioxide. This is calcination.

Step 3: Analyze reaction (B): $\mathrm{2ZnS (s) + 3}{\mathrm{O}_\mathrm{2}}\mathrm{(g)}\xrightarrow{\mathrm{\Delta }}\mathrm{2ZnO (s) + 2S}{\mathrm{O}_\mathrm{2}}\mathrm{(g)}$ \nThis reaction involves heating zinc sulfide in the presence of oxygen, producing zinc oxide and sulfur dioxide. This is roasting.

Why other options are wrong:
- Option B: Both reactions are not roasting because reaction (A) is calcination.
- Option C: Both reactions are not calcination because reaction (B) is roasting.
- Option D: (A) is not roasting and (B) is not calcination. This is the opposite of the correct answer.

Key Concepts:
- Calcination: Heating a carbonate ore to decompose it in the absence of air.
- Roasting: Heating a sulfide ore in the presence of air to convert it to an oxide.

Memory Aids:
- Calcination: "Carbonate" and "CO2" release.
- Roasting: "Sulfide" and "Oxygen" reaction.

Quick Tips:
- Remember the key difference between calcination and roasting: calcination is done in the absence of air, while roasting is done in the presence of air.

22 Easy

22 of 69Question permalink

Remembering +4 | -1

The iron obtained from the blast furnace is called:

View answer and explanation

Correct option: A

Pig iron

Option A (Pig iron) is correct because the iron obtained directly from a blast furnace is known as pig iron.

Solution approach

Correct Answer + Core Reason: Pig iron. The direct product of a blast furnace is called pig iron.

Step-by-Step Solution:

Step 1: Identify the process: The question refers to the iron produced directly from a blast furnace.

Step 2: Recall the terminology: The iron obtained from a blast furnace is known as pig iron. It is impure and needs further processing.

Step 3: Conclusion: Therefore, the answer is pig iron.

Why other options are wrong:
- Option B: Cast iron is produced by re-melting pig iron, often with the addition of scrap metal.
- Option C: Wrought iron is an iron alloy with a very low carbon content in contrast to cast iron. It is tough, malleable, ductile, and easily welded.
- Option D: Steel is an alloy of iron and carbon, with the carbon content between 0.02% and 2.14% by weight. It is produced from pig iron by reducing the carbon content and adding other alloying elements.

Key Concepts:
- Metallurgy
- Iron production
- Blast furnace
- Types of iron

Memory Aids:
- Pig iron is the \"raw\" iron from the furnace.

Quick Tips:
- Remember the order of processing: Blast furnace -> Pig iron -> Cast iron/Steel/Wrought iron

23 Easy

23 of 69Question permalink

Understanding +4 | -1

In froth floatation process for the purification of ores, the particles of ore float because

View answer and explanation

Correct option: A

Their surface is not easily wetted by water

Option A (Their surface is not easily wetted by water) is correct because the ore particles are coated with oil, making them hydrophobic and allowing them to float with the froth.

Solution approach

Correct Answer + Core Reason: Their surface is not easily wetted by water. This is the principle behind froth flotation, where hydrophobic ore particles attach to air bubbles.

Step-by-Step Solution:

Step 1: Define froth flotation. Froth flotation is a process used to separate hydrophobic materials from hydrophilic materials.

Step 2: Explain the role of oil. In froth flotation, oil (e.g., pine oil) is added to selectively wet the ore particles, making them hydrophobic.

Step 3: Explain the role of froth. Air is blown through the mixture, creating froth. The hydrophobic ore particles attach to the air bubbles in the froth and rise to the surface.

Step 4: Explain why the ore particles float. The ore particles float because they are attached to the air bubbles and their surface is not easily wetted by water.

Why other options are wrong:
- Option B: They are light. While some ore particles may be lighter than gangue particles, this is not the primary reason they float in froth flotation. The key is their hydrophobic nature.
- Option C: They are insoluble. Insolubility is not the primary reason for the ore particles to float. The selective wetting by oil and attachment to air bubbles are the main factors.
- Option D: They bear electrostatic charge. Electrostatic charge can play a role in some separation techniques, but it is not the fundamental principle behind froth flotation.

Key Concepts:
- Froth Flotation
- Hydrophobicity
- Hydrophilicity
- Selective Wetting

Memory Aids:
- Froth: Think of \"floating on froth.\"

Quick Tips:
- Remember that froth flotation separates materials based on their affinity for water (hydrophobicity vs. hydrophilicity).

24 Easy

24 of 69Question permalink

Understanding +4 | -1

Which of the following reaction is an example of calcination process?

View answer and explanation

Correct option: D

MgC{O_3}MgO + C{O_2}

Option D (

MgC{O_3}MgO + C{O_2}

) is correct because calcination involves heating a carbonate ore to drive off carbon dioxide, resulting in a metal oxide.

Solution approach

Correct Answer + Core Reason: $MgC{O_3}MgO + C{O_2}$ . This reaction represents the calcination of magnesium carbonate.

Step-by-Step Solution:

Step 1: Define calcination: Calcination is a process of heating an ore to a high temperature in the absence or limited supply of air to drive off volatile impurities or to decompose the ore.

Step 2: Identify the calcination reaction: The decomposition of magnesium carbonate ( $MgC{O_3}$ ) into magnesium oxide ( $MgO$ ) and carbon dioxide ( $C{O_2}$ ) is a typical example of calcination.

Step 3: Evaluate the other options: The other options represent different types of reactions (e.g., oxidation, roasting).

Step 4: Conclusion: $MgC{O_3}MgO + C{O_2}$ is the correct answer.

Why other options are wrong:
- **Option A ( $2Ag + 2HCl + \left[ O \right]2AgCl + {H_2}O$ ): This is not a calcination reaction; it's a reaction involving silver, hydrochloric acid, and oxidation.
- Option B ( $2Zn + {O_2}2ZnO$ ): This is an oxidation reaction, not calcination.
- Option C ( $2ZnS + 3{O_2}2ZnO + 2S{O_2}$ ): This is a roasting reaction, where a sulfide ore is heated in the presence of air.

Key Concepts:
- Calcination
- Roasting
- Metallurgical processes

Memory Aids:
- Calcination = Carbonate Decomposition

Quick Tips:**
- Know the difference between calcination, roasting, and smelting.

25 Easy

25 of 69Question permalink

Understanding +4 | -1

All ores are minerals, while all minerals are not ores because

View answer and explanation

Correct option: C

The metal cannot be extracted economically from all the minerals

Option C (The metal cannot be extracted economically from all the minerals) is correct because for a mineral to be considered an ore, the metal must be extracted from it profitably.

Solution approach

Correct Answer + Core Reason: The metal cannot be extracted economically from all the minerals. Ores must be economically viable for metal extraction.

Step-by-Step Solution:
Step 1: Define the terms 'mineral' and 'ore'.
Step 2: A mineral is a naturally occurring inorganic solid with a definite chemical composition and crystalline structure.
Step 3: An ore is a mineral from which a metal can be extracted economically.

Why other options are wrong:
- Option A: Minerals can be simple or complex, but this doesn't define the difference between ores and minerals.
- Option B: Minerals and ores are both obtained from mines, so this is not a differentiating factor.
- Option D: Only C is correct.

Key Concepts:
- Minerals and ores
- Economic viability of metal extraction

Memory Aids:
- Ores are economically viable minerals.

Quick Tips:
- Understand the definitions of minerals and ores.

26 Easy

26 of 69Question permalink

Remembering +4 | -1

Oxford process is used in extraction of:

View answer and explanation

Correct option: D

Ni

Option D (Ni) is correct because the Oxford process is specifically used in the extraction of nickel.

Solution approach

Correct Answer + Core Reason: Ni. The Oxford process is used in the extraction of Nickel.

Step-by-Step Solution:

Step 1: Recall the different metallurgical processes used for metal extraction.

Step 2: The Oxford process is a specific method used in the extraction of nickel from its ores.

Step 3: This process typically involves roasting the ore followed by reduction to obtain nickel.

Step 4: Conclude that the Oxford process is used for nickel extraction.

Why other options are wrong:
- Option A: Fe is incorrect. Iron extraction uses processes like the blast furnace method.
- Option B: Co is incorrect. Cobalt extraction involves different methods, not the Oxford process.
- Option C: Pt is incorrect. Platinum extraction involves complex processes using specific reagents.

Key Concepts:
- Oxford process.
- Nickel extraction.
- Metallurgical processes.

Memory Aids:
- Associate Oxford with Nickel.

Quick Tips:
- Remember specific processes associated with particular metals.

27 Easy

27 of 69Question permalink

Understanding +4 | -1

Electrolytic reduction of alumina to aluminium by Hall-Heroult process is carried out

View answer and explanation

Correct option: C

In the presence of cryolite which forms a melt with lower melting point

Option C is correct because cryolite (Na3AlF6) lowers the melting point of alumina and increases its conductivity, facilitating electrolysis.

Solution approach

Correct Answer + Core Reason: In the presence of cryolite which forms a melt with lower melting point. Cryolite lowers the melting point and increases conductivity.

Step-by-Step Solution:

Step 1: Alumina (Al2O3) has a very high melting point, making its direct electrolysis uneconomical.

Step 2: The Hall-Heroult process involves dissolving alumina in molten cryolite (Na3AlF6).

Step 3: Cryolite lowers the melting point of the mixture and increases the electrical conductivity of the solution.

Step 4: Electrolysis is then carried out on this mixture to obtain aluminum.

Why other options are wrong:
- Option A: NaCl is not used in the Hall-Heroult process. Cryolite is the primary additive.
- Option B: Fluorite (CaF2) is sometimes added in small amounts to further lower the melting point, but cryolite is the main component.
- Option D: Cryolite forms a melt with a *lower* melting point, not a higher one.

Key Concepts:
- Hall-Heroult process
- Electrolytic reduction
- Role of cryolite in alumina electrolysis

Memory Aids:
- Cryolite = Lower Melting Point

Quick Tips:
- Remember the key role of cryolite in the Hall-Heroult process for aluminum extraction.

28 Easy

28 of 69Question permalink

Remembering +4 | -1

Chalcopyrites is an ore of

View answer and explanation

Correct option: B

Copper

Option B (Copper) is correct because chalcopyrite (CuFeS2) is a major ore of copper.

Solution approach

Correct Answer + Core Reason: Copper. Chalcopyrite (CuFeS2) is a major ore of copper.

Step-by-Step Solution:

Step 1: Recall the composition of Chalcopyrite.

Step 2: Chalcopyrite has the formula CuFeS2.

Step 3: Identify the metals present in Chalcopyrite. It contains Copper (Cu), Iron (Fe), and Sulfur (S).

Step 4: Chalcopyrite is a significant source of Copper.

Why other options are wrong:
- Option A: Gallium is incorrect. Gallium is not a major component of chalcopyrite.
- Option C: Calcium is incorrect. Calcium is not a component of chalcopyrite.
- Option D: Magnesium is incorrect. Magnesium is not a component of chalcopyrite.

Key Concepts:
- Chalcopyrite composition (CuFeS2).
- Copper ores.

Memory Aids:
- Cu in CuFeS2 stands for Copper.

Quick Tips:
- Remember the common ores of important metals.

29 Easy

29 of 69Question permalink

Remembering +4 | -1

Iron is manufactured from the ore

View answer and explanation

Correct option: A

Haematite

Option A (Haematite) is correct because haematite is the primary ore from which iron is manufactured.

Solution approach

Correct Answer + Core Reason: Haematite is the main ore for iron production.

Step-by-Step Solution:

Step 1: Identify the common ores of iron.

Step 2: Haematite ( $Fe_2O_3$ ) is a major iron ore.

Step 3: Consider other options: Cryolite is used in aluminum extraction, Bauxite is the ore of aluminum, and Chalcopyrite is an ore of copper.

Step 4: Conclude that Haematite is the correct answer.

Why other options are wrong:
- Option B: Cryolite is used in the electrolytic refining of Aluminum.
- Option C: Bauxite is the principal ore of Aluminum.
- Option D: Chalcopyrite is a copper iron sulfide mineral and the most abundant copper ore.

Key Concepts:
- Ores of metals
- Iron extraction

Memory Aids:
- Remember Haematite is the "hematoma" of iron ores, the most important one.

Quick Tips:
- Memorize the common ores of important metals.

30 Easy

30 of 69Question permalink

Remembering +4 | -1

Which is not an ore of magnesium?

View answer and explanation

Correct option: C

Gypsum

Option C (Gypsum) is correct because gypsum is calcium sulfate dihydrate (

\mathrm{CaSO_4 \cdot 2H_2O}

), while carnallite, dolomite, and magnesite are magnesium-containing minerals.

Solution approach

Correct Answer + Core Reason: Gypsum. Gypsum is not an ore of magnesium.

Step-by-Step Solution:

Step 1: Identify the chemical formulas of the given minerals:
- Carnallite: $\mathrm{KCl} \cdot \mathrm{MgCl}_2 \cdot 6{\mathrm{H}_2}\mathrm{O}$
- Dolomite: $\mathrm{CaCO}_3 \cdot \mathrm{MgCO}_3$
- Gypsum: $\mathrm{CaSO}_4 \cdot 2{\mathrm{H}_2}\mathrm{O}$
- Magnesite: $\mathrm{MgCO}_3$

Step 2: Determine which mineral does not contain magnesium: Gypsum ( $\mathrm{CaSO_4 \cdot 2H_2O}$ ) does not contain magnesium.

Step 3: Conclusion: Gypsum is the correct answer.

Why other options are wrong:
- Option A (Carnallite): Carnallite contains magnesium chloride.
- Option B (Dolomite): Dolomite contains magnesium carbonate.
- Option D (Magnesite): Magnesite is magnesium carbonate itself.

Key Concepts:
- Mineral identification
- Chemical formulas of minerals
- Magnesium ores

Memory Aids:
- Remember the formulas of common magnesium ores.

Quick Tips:
- Know the chemical formulas of common minerals and their metal content.

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