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Basics of Carbon and Allotropy MCQs
Q1
Which term describes an element that exists in two or more physical forms in the same state?
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Answer: B) Allotropy
First, allotropy means one element can take several structural forms. Moreover, the atoms in each form join together in a different pattern. As a result, the forms show different physical properties. However, many of their chemical reactions look very similar. Finally, carbon, sulphur, and phosphorus show this behaviour.
Q2
Which property lets carbon atoms join into long chains and rings?
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Answer: C) Catenation
In fact, carbon has four valence electrons and forms four strong covalent bonds. Also, the carbon–carbon bond stays very strong and stable. For this reason, carbon builds long chains, rings, and branched shapes. Still, silicon shows this property only to a small extent. Overall, catenation explains the huge number of carbon compounds.
Q3
Which pair contains two allotropes of carbon?
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Answer: D) Diamond and graphite
To begin with, diamond and graphite both contain only carbon atoms. Additionally, their atoms follow very different bonding patterns. Because of this, diamond looks transparent and hard, while graphite looks dark and soft. For instance, oxygen and ozone form an allotrope pair of oxygen, not carbon. In short, you must match each pair with its own element.
Q4
Which gas forms when diamond or graphite burns completely in excess oxygen?
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Answer: A) Carbon dioxide
Earlier, in 1797, Smithson Tennant burned diamond and collected the gas. Next, he showed that the gas was carbon dioxide. As a result, people accepted that diamond contains only carbon. In contrast, incomplete burning in limited oxygen gives carbon monoxide. Overall, this test proves that all carbon allotropes share the same element.
Diamond MCQs: Structure, Properties, and Uses
Q5
Which type of hybridisation do carbon atoms show in diamond?
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Answer: C) sp³
Initially, each carbon atom in diamond forms four single bonds. Besides, these four bonds point toward the corners of a tetrahedron. Hence, the structure forms a strong three-dimensional network. But graphite uses sp² hybridisation and builds flat layers instead. In summary, the shape of the bonds decides the properties.
Q6
Which property makes diamond ideal for glass cutters and drill bits?
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Answer: B) Extreme natural hardness
In fact, diamond ranks 10 on the Mohs hardness scale. Furthermore, workers fit diamond tips on drills, saws, and glass cutters. Because of this, these tools cut through rock, metal, and glass easily. Yet diamond can still crack if someone hits it sharply. Overall, hardness and thermal conductivity make diamond a valuable industrial material.
Q7
How many milligrams does one metric carat weigh?
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Answer: D) 200 mg
First, jewellers measure diamond weight in carats. Also, one carat equals 0.2 grams. Therefore, a five-carat diamond weighs exactly one gram. However, the karat used for gold measures purity, not weight. Finally, factors such as cut, colour, and clarity also affect the price of a diamond.
Q8
Which Indian state contains the Panna diamond-mining region?
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Answer: A) Madhya Pradesh
To begin with, the Majhgawan mine near Panna remains India’s best-known working diamond mine. In addition, the National Mineral Development Corporation runs this mine. As a result, Madhya Pradesh stands out as the leading diamond-producing state. On the other hand, the Deccan region supplied famous diamonds in earlier centuries. Thus, students should link Panna with Madhya Pradesh in the exam.
Q9
Which conditions help scientists convert graphite into synthetic diamond?
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Answer: C) High pressure and high temperature
Later, General Electric scientists made synthetic diamonds in 1954. Moreover, the method squeezes graphite under extreme pressure and heat. For this reason, people call it the HPHT method. In contrast, chemical vapour deposition grows diamond from carbon-rich gas. In conclusion, labs now make diamonds for both jewellery and industry.
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Graphite and Graphene MCQs
Q10
Which feature of graphite lets it conduct electricity?
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Answer: A) Delocalised electrons in each layer
Next, each carbon atom in graphite forms three bonds with its neighbours. Then, one electron per atom stays free and moves within the layer. Therefore, graphite carries electric current well. In contrast, diamond uses all four electrons in bonds and acts as an insulator. Hence, makers use graphite for electrodes and battery parts.
Q11
Which force holds the layers of graphite together?
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Answer: D) Weak van der Waals forces
Also, these weak forces let the layers slide over each other. As a result, graphite feels soft and slippery. For example, people use graphite powder as a dry lubricant in machines. However, the bonds inside each layer stay very strong. Finally, graphite also stands as the most stable form of carbon under normal conditions.
Q12
Which material do manufacturers mix with clay to make pencil leads?
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Answer: B) Graphite
In fact, Abraham Gottlob Werner named graphite in 1789 from a Greek word meaning “to write.” Besides, pencil lead contains no real lead. Instead, makers blend graphite with clay in different ratios. Therefore, harder pencils contain more clay, while softer ones contain more graphite. For instance, a 2B pencil writes darker than an HB pencil.
Q13
Which scientists isolated graphene at the University of Manchester in 2004?
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Answer: B) Andre Geim and Konstantin Novoselov
Initially, the two scientists peeled thin flakes from graphite with sticky tape. Afterward, they placed the flakes on a silicon wafer and studied them. As a result, they isolated single layers of carbon atoms. Later, the Nobel Committee honoured them with the 2010 Nobel Prize in Physics. In short, this work opened a new field of material science.
Q14
How many atoms thick is a sheet of graphene?
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Answer: C) One atom
First, graphene forms a single layer of carbon atoms in a honeycomb pattern. Moreover, this thin sheet conducts heat and electricity extremely well. Because of this, researchers test it in flexible screens, sensors, and batteries. Still, making large, flawless sheets cheaply remains a challenge. To sum up, graphene is one atom thick yet very strong.
Fullerenes, Nanotubes, and Amorphous Carbon MCQs
Q15
How many carbon atoms does a buckminsterfullerene molecule contain?
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Answer: A) 60 atoms
To begin with, Harold Kroto, Robert Curl, and Richard Smalley discovered C60 in 1985. As a result, they shared the 1996 Nobel Prize in Chemistry. Moreover, C60 belongs to a larger family of molecules called fullerenes. In contrast, C70 looks more like a rugby ball. Finally, the name honours Buckminster Fuller, who designed geodesic domes.
Q16
Which everyday object does the shape of a C60 molecule resemble?
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Answer: D) A football
In fact, the C60 cage has 12 pentagons and 20 hexagons, just like a football. Besides, each of the 60 corners holds one carbon atom. Because of this, people also call C60 a buckyball. However, unlike diamond and graphite, fullerene dissolves in some solvents such as toluene. Thus, fullerene forms small molecules, while diamond and graphite form giant networks.
Q17
Which scientist reported carbon nanotubes in 1991 and drew wide attention to them?
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Answer: C) Sumio Iijima
Next, Sumio Iijima observed the tubes under an electron microscope at NEC in Japan. In addition, a carbon nanotube resembles a graphene sheet rolled into a cylinder. Therefore, nanotubes show great strength and good electrical conduction. On the other hand, single-walled and multi-walled tubes differ in structure and use. In short, nanotubes could improve sports gear, electronics, and batteries.
Q18
How do manufacturers make coke from coal?
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Answer: A) Heating it strongly without air
Initially, strong heating without air drives out gases and tar from coal. Afterward, a hard, porous, carbon-rich solid remains, and people call it coke. For example, blast furnaces use coke to reduce iron ore into iron. In contrast, burning coal in excess air mainly gives carbon dioxide and ash. Hence, coke plays a key role in the steel industry.
Q19
Which property makes activated charcoal useful in water purifiers?
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Answer: B) Strong adsorption ability
Also, charcoal forms when people heat wood in a limited supply of air. Then, steam treatment makes it highly porous. Because of this, its large surface area traps gases, colours, and impurities. For instance, gas masks and water filters contain activated charcoal. Yet adsorption differs from absorption because the particles stick only to the surface.
Q20
Which type of coal contains the highest percentage of carbon?
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Answer: D) Anthracite
In fact, coal forms slowly from buried plants over millions of years. Moreover, heat and pressure raise the carbon content step by step. Consequently, the order runs from peat to lignite, then bituminous coal, and finally anthracite. However, anthracite burns with little smoke and gives high heat. Overall, coal contains mostly amorphous carbon along with impurities.
CONCLUSION
Final Thoughts on Allotropes of Carbon MCQs
Overall, these allotropes of carbon MCQs cover the key facts about diamond, graphite, graphene, fullerenes, and amorphous carbon. Moreover, they show how the arrangement of atoms changes the properties of a single element. For example, diamond stays hard and insulating, but graphite conducts electricity and feels slippery. Therefore, you should revise the structure, properties, and uses of each allotrope together. Next, practise the MCQs again and review every Extra Information note carefully. Then, take timed tests so that you can improve your speed and accuracy. In addition, make short notes on dates, names, and discoveries, such as the 1985 fullerene discovery. Finally, keep this practice going for RRB NTPC, SSC, and UPSC exams, because steady effort brings steady progress. So, keep practising with a smile, because every small step builds your confidence.