Metals, Non-Metals and Metallurgy: Properties, Reactivity Series, Ores and Extraction Processes

Metals, Non-Metals and Metallurgy is an important chapter in General Science and Chemistry for competitive examinations. It deals with the physical and chemical properties of metals and non-metals, the reactivity series, minerals and ores, and the methods used to extract metals from their ores.

Metals such as iron, copper, aluminium and zinc are essential in everyday life and industrial development. However, most metals are not found in nature in their pure form. They occur as compounds in minerals and must be extracted through suitable metallurgical processes.

In this article, we will cover the basic concepts, important chemical reactions, extraction methods, practical applications, exam-oriented facts and MCQs for SSC, Railway, WBCS, UPSC, State PSC and other competitive examinations.

1. What Are Metals?

Metals are elements that generally lose electrons to form positive ions (cations). They are usually hard, shiny, malleable, ductile and good conductors of heat and electricity.

Examples of common metals include iron (Fe), copper (Cu), aluminium (Al), zinc (Zn), gold (Au), silver (Ag), sodium (Na), calcium (Ca) and magnesium (Mg).

Important Characteristics of Metals

• Metals generally have a shiny surface, known as metallic lustre.
• They are generally good conductors of heat and electricity.
• Most metals are malleable, meaning they can be beaten into thin sheets.
• Most metals are ductile, meaning they can be drawn into wires.
• Most metals are solids at room temperature.
• Metals generally have high tensile strength and are often strong.
• Most metals have high melting and boiling points, although there are exceptions.
• Metals generally form positive ions by losing electrons.

2. Physical Properties of Metals

1. Lustre

Most metals have a shiny surface when freshly cut or polished. This property is called metallic lustre. Gold, silver, copper and aluminium are common examples.

2. Malleability

Malleability is the ability of a material to be hammered or rolled into thin sheets without breaking.

Example: Aluminium is used to make foil, while gold and silver can be beaten into very thin sheets.

3. Ductility

Ductility is the ability of a material to be drawn into thin wires.

Example: Copper and aluminium are widely used in electrical wiring because of their ductility and electrical conductivity.

4. Conductivity

Metals are generally good conductors of heat and electricity. Silver and copper are among the best electrical conductors, while aluminium is also widely used in electrical transmission.

5. Sonority

Metals generally produce a ringing sound when struck. This property is known as sonority. It is one reason metals are used in bells and musical instruments.

6. Hardness and Strength

Many metals are hard and strong. However, hardness varies considerably. Sodium and potassium are soft metals and can be cut with a knife, whereas iron and chromium are much harder.

7. Density

Many metals have relatively high density. However, some metals such as lithium, sodium and potassium have low densities.

Important Exceptions in Metals

• Mercury (Hg) is liquid at room temperature.
• Sodium and potassium are soft metals.
• Gallium and caesium have melting points close to ordinary room temperature.
• Aluminium is comparatively light despite being a metal.
• Tungsten has an exceptionally high melting point.

3. Chemical Properties of Metals

Metals generally lose electrons during chemical reactions and form positive ions. Their chemical behaviour depends largely on their position in the reactivity series.

1. Reaction with Oxygen

Most metals react with oxygen to form metal oxides.

General reaction:

Metal + Oxygen → Metal oxide

Example: Magnesium burning in oxygen

2Mg + O₂ → 2MgO

Magnesium burns with a dazzling white flame and produces white magnesium oxide.

Metal oxides are generally basic, although some are amphoteric. Aluminium oxide (Al₂O₃) and zinc oxide (ZnO) are amphoteric oxides because they react with both acids and bases.

2. Reaction with Water

Different metals react with water at different rates.

Metal	Reaction with water
Potassium and Sodium	React violently with cold water.
Calcium	Reacts with cold water less vigorously than sodium.
Magnesium	Reacts very slowly with cold water but reacts with hot water and steam.
Aluminium	Protected by a thin oxide layer; reacts with steam under suitable conditions.
Zinc	Reacts with steam to form zinc oxide and hydrogen.
Iron	Reacts with steam at high temperature.
Copper, Silver and Gold	Do not react with water under ordinary conditions.

Example: Sodium and water

2Na + 2H₂O → 2NaOH + H₂↑

Example: Iron and steam

3Fe + 4H₂O (steam) → Fe₃O₄ + 4H₂↑

3. Reaction with Dilute Acids

Metals above hydrogen in the reactivity series generally react with dilute hydrochloric acid or dilute sulphuric acid to produce a salt and hydrogen gas.

Metal + Dilute acid → Salt + Hydrogen gas

Example: Zinc and hydrochloric acid

Zn + 2HCl → ZnCl₂ + H₂↑

Copper, silver and gold do not normally liberate hydrogen from dilute hydrochloric acid because they are below hydrogen in the reactivity series.

4. Displacement Reactions

A more reactive metal can displace a less reactive metal from its salt solution.

Example:

Fe + CuSO₄ → FeSO₄ + Cu

Iron displaces copper from copper sulphate solution because iron is more reactive than copper. The blue solution gradually turns green, and copper is deposited.

5. Reaction with Chlorine

Many metals react with chlorine to form metal chlorides.

Example:

2Na + Cl₂ → 2NaCl

4. What Are Non-Metals?

Non-metals are elements that generally gain electrons or share electrons during chemical reactions. They usually lack the characteristic physical properties of metals.

Examples include oxygen (O), nitrogen (N), hydrogen (H), carbon (C), sulphur (S), phosphorus (P), chlorine (Cl) and bromine (Br).

Physical Properties of Non-Metals

• Most non-metals are poor conductors of heat and electricity.
• They are generally non-lustrous.
• Solid non-metals are generally brittle and cannot be beaten into sheets.
• They are generally neither malleable nor ductile.
• Many non-metals have relatively low densities.
• Non-metals can exist as solids, liquids or gases at room temperature.

Important Exceptions in Non-Metals

• Graphite, an allotrope of carbon, conducts electricity.
• Iodine has a shiny appearance, despite being a non-metal.
• Diamond, another allotrope of carbon, is extremely hard.
• Bromine is a liquid non-metal at room temperature.
• Hydrogen, oxygen, nitrogen and chlorine are gases at room temperature.

5. Chemical Properties of Non-Metals

1. Reaction with Oxygen

Non-metals generally react with oxygen to form non-metal oxides. Many non-metal oxides are acidic, while some are neutral.

Example:

C + O₂ → CO₂

Carbon dioxide is an acidic oxide.

Another example:

S + O₂ → SO₂

2. Reaction with Water

Non-metals generally do not react with water in the same way as highly reactive metals. Some non-metal oxides, however, react with water to form acids.

Example:

CO₂ + H₂O ⇌ H₂CO₃

3. Reaction with Acids

Non-metals generally do not displace hydrogen from dilute acids because they do not readily lose electrons like reactive metals.

4. Formation of Covalent Compounds

Non-metals commonly form covalent bonds by sharing electrons.

Examples: Water (H₂O), methane (CH₄) and carbon dioxide (CO₂).

6. Difference Between Metals and Non-Metals

Metals	Non-Metals
Generally lustrous	Generally non-lustrous
Generally malleable	Solid forms are generally brittle
Generally ductile	Generally non-ductile
Generally good conductors	Generally poor conductors
Usually form positive ions	Often form negative ions or covalent bonds
Oxides are generally basic or amphoteric	Oxides are generally acidic or neutral
Usually have metallic bonding in elemental form	Often have covalent bonding in elemental form
Examples: Fe, Cu, Al, Zn	Examples: O, N, S, C, Cl

7. Metalloids

Metalloids are elements that show properties intermediate between metals and non-metals. They are important in electronics and semiconductor technology.

Common examples: Boron, Silicon, Germanium, Arsenic, Antimony and Tellurium.

Silicon and germanium are particularly important because they are used as semiconductors in electronic devices, solar cells and computer components.

8. Reactivity Series of Metals

The reactivity series is an arrangement of metals in decreasing order of their chemical reactivity. It helps predict how metals react with water, acids and salt solutions, and how they can be extracted from ores.

Reactivity series (most reactive to least reactive):

K > Na > Ca > Mg > Al > Zn > Fe > Pb > (H) > Cu > Hg > Ag > Au

Metal	Symbol	General behaviour
Potassium	K	Extremely reactive
Sodium	Na	Reacts vigorously with cold water
Calcium	Ca	Reacts with cold water
Magnesium	Mg	Reacts with hot water and steam
Aluminium	Al	Protected by a thin oxide layer
Zinc	Zn	Reacts with dilute acids and steam
Iron	Fe	Reacts with steam and rusts in moist air
Lead	Pb	Less reactive than iron
Hydrogen	H	Reference point, not a metal
Copper	Cu	Does not displace hydrogen from dilute acids
Mercury	Hg	Low-reactivity metal
Silver	Ag	Very low reactivity
Gold	Au	One of the least reactive metals

Importance of the Reactivity Series

• It predicts whether one metal can displace another from a salt solution.
• It helps determine whether a metal reacts with water or dilute acids.
• It helps select the suitable extraction method for a metal.
• It explains why highly reactive metals are generally extracted by electrolysis.
• It helps explain corrosion and the relative stability of metals.

9. Minerals and Ores

Metals are usually found in nature in the form of compounds such as oxides, sulphides and carbonates. These naturally occurring substances are called minerals.

What Are Minerals?

Minerals are naturally occurring substances in the Earth's crust that contain metals or their compounds.

What Are Ores?

Ores are minerals from which metals can be extracted conveniently and economically. Every ore is a mineral, but every mineral is not necessarily an ore.

Difference Between Minerals and Ores

Minerals	Ores
Naturally occurring substances containing metals or their compounds.	Minerals suitable for economical extraction of metals.
All minerals need not be commercially useful.	Ores are commercially useful sources of metals.
May contain low concentrations of metal.	Contain sufficient valuable material for extraction under prevailing economic conditions.

Important Ores of Common Metals

Metal	Ore	Chemical formula
Iron	Haematite	Fe2O3
Iron	Magnetite	Fe3O4
Iron	Siderite	FeCO3
Iron	Iron pyrites	FeS2
Aluminium	Bauxite	Aluminium oxide hydrate; variable composition
Aluminium	Corundum	Al2O3
Copper	Chalcopyrite (Copper pyrites)	CuFeS2
Copper	Cuprite	Cu2O
Copper	Malachite	CuCO3·Cu(OH)2
Zinc	Zinc blende (Sphalerite)	ZnS
Zinc	Calamine (Smithsonite)	ZnCO3
Zinc	Zincite	ZnO

10. Metallurgy: Meaning and Main Steps

Metallurgy is the branch of science and technology concerned with the extraction of metals from their ores, their purification and the preparation of useful alloys.

The extraction method depends on the nature of the ore and the reactivity of the metal.

Main Steps in Metallurgy

1. Crushing and Grinding

The mined ore is broken into smaller pieces and ground into a fine powder. This helps separate the valuable mineral from unwanted material.

2. Concentration of Ore (Ore Dressing)

Concentration is the process of removing unwanted impurities, known as gangue, from the ore.

Important methods include:

• Hydraulic washing: Uses differences in density to separate heavier ore particles from lighter impurities.
• Magnetic separation: Uses magnetic properties to separate magnetic ore or impurities from non-magnetic materials.
• Froth flotation: Commonly used for sulphide ores. Ore particles attach to air bubbles and rise with the froth, while many impurities remain in the water.
• Leaching: Uses a suitable chemical solution to dissolve the desired component selectively, leaving much of the unwanted material behind.

3. Conversion of Ore into Oxide

Many metals are extracted more conveniently from their oxides. Sulphide and carbonate ores are often converted into oxides by roasting or calcination.

Roasting

Roasting involves heating a sulphide ore strongly in excess air or oxygen.

Example:

2ZnS + 3O₂ → 2ZnO + 2SO₂

Calcination

Calcination involves heating carbonate or hydrated ores in limited or no air to remove volatile substances such as carbon dioxide or water.

Example:

ZnCO₃ → ZnO + CO₂

4. Reduction of Metal Oxide

The metal oxide is reduced to obtain the metal. Depending on the reactivity of the metal, reduction may be carried out using carbon, carbon monoxide, another metal or electrolysis.

5. Refining of Metals

The crude metal obtained after extraction may contain impurities. Refining is used to obtain metal of the required purity.

11. Extraction of Iron

Iron is one of the most widely used metals in the world. It is extracted mainly from haematite (Fe₂O₃) in a blast furnace.

Important Iron Ores

• Haematite – Fe₂O₃
• Magnetite – Fe₃O₄
• Siderite – FeCO₃
• Iron pyrites – FeS₂

Raw Materials Used in the Blast Furnace

• Iron ore: The source of iron.
• Coke: Acts as a fuel and produces carbon monoxide, which reduces iron oxide.
• Limestone: Acts as a flux and helps remove silica impurities.
• Hot air: Supports combustion of coke.

Working of a Blast Furnace

The furnace is charged from the top with iron ore, coke and limestone. A blast of hot air is introduced near the bottom. The resulting high-temperature reactions reduce iron oxide and produce molten iron.

Important Reactions

1. Formation of carbon dioxide:

C + O₂ → CO₂

2. Formation of carbon monoxide:

CO₂ + C → 2CO

3. Reduction of haematite:

Fe₂O₃ + 3CO → 2Fe + 3CO₂

Carbon monoxide is the main reducing agent in the blast furnace.

4. Decomposition of limestone:

CaCO₃ → CaO + CO₂

5. Formation of slag:

CaO + SiO₂ → CaSiO₃

Calcium silicate is the slag. It is lighter than molten iron and can be removed separately.

Products of the Blast Furnace

• Molten pig iron: Contains a relatively high percentage of carbon and other impurities.
• Slag: Mainly contains calcium silicate and other waste components.
• Blast furnace gas: Contains gases such as nitrogen, carbon monoxide and carbon dioxide.

Pig iron can be further processed to produce cast iron or steel, depending on the desired composition and properties.

12. Extraction of Aluminium

Aluminium is a highly reactive metal. Its principal ore is bauxite. Because aluminium has a strong affinity for oxygen, it cannot be extracted economically by ordinary reduction with carbon. It is extracted by electrolysis.

Step 1: Purification of Bauxite

Bauxite contains aluminium-bearing compounds along with impurities such as iron oxides and silica. The Bayer process is commonly used to obtain purified alumina (Al₂O₃).

In the Bayer process, bauxite is treated with hot concentrated sodium hydroxide solution under suitable pressure. Aluminium compounds dissolve as sodium aluminate, while many insoluble impurities are separated. Aluminium hydroxide is then precipitated and heated to form alumina.

Heating aluminium hydroxide:

2Al(OH)₃ → Al₂O₃ + 3H₂O

Step 2: Electrolytic Reduction (Hall-Héroult Process)

Purified alumina is dissolved in molten cryolite (Na₃AlF₆) and electrolysed using carbon electrodes.

Why is cryolite used?

• It lowers the operating temperature compared with the melting point of pure alumina.
• It improves the electrical conductivity of the electrolyte.
• It helps dissolve alumina in the molten bath.

Electrode Reactions

At the cathode:

Al³⁺ + 3e⁻ → Al

At the anode:

Oxide ions lose electrons to form oxygen. The oxygen reacts with the carbon anode, producing mainly carbon dioxide under normal operating conditions.

Overall simplified reaction:

2Al₂O₃ + 3C → 4Al + 3CO₂

Molten aluminium collects at the bottom of the electrolytic cell and is periodically removed.

13. Extraction of Copper

Copper is an important metal used in electrical wiring, electronic equipment, pipes and alloys. One of its major ores is chalcopyrite (CuFeS₂), also known as copper pyrites.

Important Copper Ores

• Chalcopyrite – CuFeS₂
• Cuprite – Cu₂O
• Malachite – CuCO₃·Cu(OH)₂
• Chalcocite – Cu₂S

Steps in the Extraction of Copper from Sulphide Ore

1. Concentration

Chalcopyrite ore is concentrated mainly by the froth flotation process.

2. Roasting and Smelting

The concentrated sulphide ore is heated in air and processed in a furnace. Iron sulphide is oxidised, and iron oxide combines with silica flux to form iron silicate slag.

Important reactions:

2FeS + 3O₂ → 2FeO + 2SO₂

FeO + SiO₂ → FeSiO₃

The molten sulphide mixture, commonly called copper matte, contains mainly copper sulphide (Cu₂S) and iron sulphide (FeS).

3. Conversion to Blister Copper

Air or oxygen is blown through the matte in a converter. Iron sulphide is oxidised and removed as slag. Part of the copper sulphide is oxidised to copper oxide, which then reacts with remaining copper sulphide to form copper metal.

Important reaction:

2Cu₂O + Cu₂S → 6Cu + SO₂

The copper obtained is called blister copper because escaping sulphur dioxide gas creates a blistered appearance on its surface.

4. Electrolytic Refining of Copper

Blister copper is refined by electrolysis.

• Anode: Impure copper
• Cathode: Thin sheet of pure copper
• Electrolyte: Acidified copper sulphate solution

At the anode:

Cu → Cu²⁺ + 2e⁻

At the cathode:

Cu²⁺ + 2e⁻ → Cu

Pure copper gets deposited on the cathode. Some less reactive impurities settle below the anode as anode mud, while other impurities may remain in solution.

14. Extraction of Zinc

Zinc is widely used for galvanising iron and steel, manufacturing alloys and producing dry-cell batteries. Its principal ore is zinc blende or sphalerite (ZnS).

Important Zinc Ores

• Zinc blende (Sphalerite) – ZnS
• Calamine (Smithsonite) – ZnCO₃
• Zincite – ZnO

Steps in Zinc Extraction

1. Concentration of Ore

Zinc sulphide ore is generally concentrated by froth flotation.

2. Roasting

The concentrated zinc sulphide ore is heated in excess air to convert it into zinc oxide.

Reaction:

2ZnS + 3O₂ → 2ZnO + 2SO₂

3. Reduction

Zinc oxide is heated with coke or another suitable reducing agent at high temperature.

Reaction:

ZnO + C → Zn + CO

Zinc is produced as vapour at the furnace temperature and is then cooled and condensed.

4. Refining

The crude zinc is purified by suitable refining methods, which may include distillation or electrolytic refining, depending on the process and required purity.

15. Comparison of Extraction Methods

Metal	Main ore	Important extraction method	Key process
Iron	Haematite (Fe2O3)	Reduction in blast furnace	Reduction by carbon monoxide
Aluminium	Bauxite	Electrolysis of alumina	Hall-Héroult process
Copper	Chalcopyrite (CuFeS2)	Roasting, smelting and conversion	Blister copper followed by electrolytic refining
Zinc	Zinc blende (ZnS)	Roasting followed by reduction	Reduction of ZnO using carbon

16. Corrosion of Metals

Corrosion is the gradual destruction of a metal due to chemical or electrochemical reactions with its surroundings.

Rusting of Iron

Rusting occurs when iron reacts with oxygen and moisture. The reddish-brown substance formed is hydrated iron(III) oxide, commonly represented as Fe₂O₃·xH₂O.

Both oxygen and water are necessary for ordinary rusting. Salts and acidic conditions can accelerate corrosion.

Methods of Preventing Corrosion

• Painting: Creates a protective barrier between metal and air or moisture.
• Oiling and greasing: Prevents contact with moisture and oxygen.
• Galvanisation: Coats iron or steel with zinc.
• Electroplating: Deposits a protective layer of another metal.
• Alloying: Improves resistance to corrosion, as in stainless steel.
• Cathodic protection: Uses a sacrificial anode or an impressed current to protect the metal.

17. Alloys and Their Uses

An alloy is a material made by combining two or more elements, at least one of which is a metal. Alloys are developed to improve properties such as strength, hardness, corrosion resistance and durability.

Alloy	Main composition	Uses
Brass	Copper + Zinc	Utensils, musical instruments and fittings
Bronze	Copper + Tin	Statues, medals and bearings
Stainless steel	Iron + Chromium, usually with nickel and other elements	Kitchen equipment, medical instruments and construction
Steel	Iron + Carbon	Buildings, tools and machinery
Solder	Traditionally Tin + Lead; lead-free types also exist	Joining metal components
Duralumin	Aluminium-based alloy containing copper, magnesium and manganese	Aircraft structures and engineering
Nichrome	Nickel + Chromium, often with iron	Heating elements

18. Important One-Liner Facts for Competitive Exams

• Metals generally form positive ions by losing electrons.
• Non-metals generally form covalent bonds or gain electrons.
• Mercury is a liquid metal at room temperature.
• Bromine is a liquid non-metal at room temperature.
• Graphite is a non-metal that conducts electricity.
• Diamond is an extremely hard form of carbon.
• Gold is one of the least reactive metals.
• Potassium is more reactive than sodium.
• Hydrogen is included in the reactivity series as a reference, although it is not a metal.
• Haematite is an important ore of iron.
• Bauxite is the principal ore of aluminium.
• Chalcopyrite is an important ore of copper.
• Zinc blende is an important ore of zinc.
• Froth flotation is commonly used to concentrate sulphide ores.
• Roasting is generally used for sulphide ores.
• Calcination is generally used for carbonate and hydrated ores.
• Iron is extracted in a blast furnace.
• Carbon monoxide acts as a reducing agent in the blast furnace.
• Aluminium is extracted by electrolysis of alumina dissolved in molten cryolite.
• The Hall-Héroult process is used for aluminium extraction.
• Copper obtained from the converter is called blister copper.
• Electrolytic refining is used to obtain high-purity copper.
• Galvanisation means coating iron or steel with zinc.
• Brass is an alloy of copper and zinc.
• Bronze is an alloy of copper and tin.

19. Important Chemical Reactions for Revision

Reaction	Chemical equation
Magnesium burning	2Mg + O2 → 2MgO
Sodium and water	2Na + 2H2O → 2NaOH + H2
Zinc and hydrochloric acid	Zn + 2HCl → ZnCl2 + H2
Iron displacing copper	Fe + CuSO4 → FeSO4 + Cu
Zinc sulphide roasting	2ZnS + 3O2 → 2ZnO + 2SO2
Zinc carbonate calcination	ZnCO3 → ZnO + CO2
Zinc oxide reduction	ZnO + C → Zn + CO
Iron oxide reduction	Fe2O3 + 3CO → 2Fe + 3CO2
Limestone decomposition	CaCO3 → CaO + CO2
Slag formation	CaO + SiO2 → CaSiO3
Alumina decomposition (overall cell reaction)	2Al2O3 + 3C → 4Al + 3CO2

20. Metals, Non-Metals and Metallurgy – MCQs

Practise these multiple-choice questions to test your understanding of metals, non-metals, ores, reactivity and extraction processes.

Question 1

Which of the following metals is liquid at room temperature?

1. Iron
2. Mercury
3. Aluminium
4. Copper

Answer: B. Mercury

Explanation: Mercury is a metal that remains liquid at ordinary room temperature.

Question 2

Which non-metal is a good conductor of electricity?

1. Sulphur
2. Phosphorus
3. Graphite
4. Oxygen

Answer: C. Graphite

Explanation: Graphite conducts electricity because it has delocalised electrons that can move through its layered structure.

Question 3

Which of the following is the most reactive metal?

1. Gold
2. Copper
3. Potassium
4. Silver

Answer: C. Potassium

Explanation: Potassium is placed near the top of the common reactivity series.

Question 4

Which is the principal ore of aluminium?

1. Haematite
2. Bauxite
3. Zinc blende
4. Chalcopyrite

Answer: B. Bauxite

Explanation: Aluminium is commercially extracted from purified alumina obtained from bauxite.

Question 5

Haematite is an important ore of:

1. Copper
2. Zinc
3. Iron
4. Aluminium

Answer: C. Iron

Explanation: Haematite has the chemical formula Fe₂O₃.

Question 6

Which ore is commonly known as zinc blende?

1. ZnS
2. ZnO
3. ZnCO₃
4. FeS₂

Answer: A. ZnS

Explanation: Zinc blende, also called sphalerite, is zinc sulphide.

Question 7

Which method is commonly used to concentrate sulphide ores?

1. Froth flotation
2. Distillation
3. Crystallisation
4. Filtration only

Answer: A. Froth flotation

Explanation: Sulphide ore particles attach to air bubbles and rise with the froth.

Question 8

Roasting is generally used for the extraction of metals from:

1. Sulphide ores
2. Pure metals
3. Native gases
4. Only chloride ores

Answer: A. Sulphide ores

Explanation: Roasting heats sulphide ores in excess air or oxygen.

Question 9

Calcination is generally used for:

1. Sulphide ores only
2. Carbonate and hydrated ores
3. Pure metals
4. Alloys only

Answer: B. Carbonate and hydrated ores

Explanation: Calcination removes volatile components such as carbon dioxide and water by heating.

Question 10

Iron is extracted mainly in a:

1. Blast furnace
2. Electrolytic cell
3. Distillation column
4. Solar furnace only

Answer: A. Blast furnace

Explanation: Iron oxide is reduced by carbon monoxide in the blast furnace.

Question 11

Which substance acts as the main reducing agent in the blast furnace?

1. Oxygen
2. Carbon monoxide
3. Nitrogen
4. Water vapour

Answer: B. Carbon monoxide

Explanation: Carbon monoxide removes oxygen from iron oxide to produce iron.

Question 12

Which substance is used as a flux in the blast furnace for iron extraction?

1. Limestone
2. Sand only
3. Water
4. Sodium chloride

Answer: A. Limestone

Explanation: Limestone decomposes to calcium oxide, which combines with silica to form slag.

Question 13

The slag formed during iron extraction is mainly:

1. Calcium silicate
2. Sodium chloride
3. Iron sulphide
4. Calcium carbonate

Answer: A. Calcium silicate

Explanation: Calcium oxide reacts with silica to form CaSiO₃.

Question 14

Which process is used for the electrolytic extraction of aluminium?

1. Bessemer process
2. Hall-Héroult process
3. Bayer process only
4. Froth flotation

Answer: B. Hall-Héroult process

Explanation: Alumina dissolved in molten cryolite is electrolysed to obtain aluminium.

Question 15

Why is cryolite added during aluminium extraction?

1. To increase the melting point of alumina
2. To lower operating temperature and improve conductivity
3. To act as the source of iron
4. To produce hydrogen

Answer: B. To lower operating temperature and improve conductivity

Explanation: Cryolite helps dissolve alumina and reduces the operating temperature.

Question 16

Which is an important ore of copper?

1. Chalcopyrite
2. Bauxite
3. Haematite
4. Calamine

Answer: A. Chalcopyrite

Explanation: Chalcopyrite has the formula CuFeS₂.

Question 17

Why is copper obtained from the converter called blister copper?

1. It is always blue
2. Escaping gas creates a blistered surface
3. It is mixed with aluminium
4. It is in liquid form permanently

Answer: B. Escaping gas creates a blistered surface

Explanation: Escaping sulphur dioxide creates a blistered appearance on the copper.

Question 18

Which metal is used for galvanising iron?

1. Copper
2. Silver
3. Zinc
4. Gold

Answer: C. Zinc

Explanation: Galvanisation protects iron or steel by coating it with zinc.

Question 19

Brass is an alloy of:

1. Copper and zinc
2. Copper and tin
3. Iron and carbon
4. Aluminium and copper

Answer: A. Copper and zinc

Explanation: Brass is primarily made from copper and zinc.

Question 20

Which of the following is the correct statement?

1. Every mineral is an ore
2. Every ore is a mineral, but every mineral is not an ore
3. Ores contain no impurities
4. All metals occur freely in nature

Answer: B. Every ore is a mineral, but every mineral is not an ore

Explanation: An ore is a mineral from which a metal can be extracted economically.

21. Quick Revision Notes

• Metals: Generally lustrous, malleable, ductile and good conductors.
• Non-metals: Generally poor conductors, non-malleable and brittle when solid.
• Metalloid: Shows intermediate properties between metals and non-metals.
• Reactivity series: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au.
• Iron ore: Haematite (Fe₂O₃).
• Aluminium ore: Bauxite.
• Copper ore: Chalcopyrite (CuFeS₂).
• Zinc ore: Zinc blende (ZnS).
• Roasting: Heating sulphide ores in excess air.
• Calcination: Heating carbonate or hydrated ores in limited or no air.
• Iron extraction: Blast furnace.
• Aluminium extraction: Hall-Héroult electrolytic process.
• Copper refining: Electrolytic refining.
• Galvanisation: Coating iron or steel with zinc.
• Brass: Copper + Zinc.
• Bronze: Copper + Tin.

Conclusion

Metals, Non-Metals and Metallurgy form an important part of Chemistry and General Science. Understanding their physical and chemical properties helps explain their everyday applications, while the reactivity series helps predict chemical reactions and the methods used for metal extraction.

For competitive examinations, focus especially on the reactivity series, important ores and their chemical formulas, roasting and calcination, blast furnace reactions, the Hall-Héroult process, copper refining and common alloys.

Revise the comparison tables and practise the MCQs regularly to strengthen your preparation for SSC, Railway, WBCS, UPSC and other government examinations.

Related Study Materials

Explore more General Science and Physics study materials on CrackGK.in.