1. Which one of the following elements forms the maximum number of compounds?
(a) Hydrogen
(b) Carbon
(c) Nitrogen
(d) Oxygen
[U.P. P.C.S. (Mains) 2016]
Ans. (b) Carbon
- Out of all the elements listed, carbon makes the most compounds.
|
2. Which of the following does not consist of carbon?
(a) Diamond
(b) Graphite
(c) Coal
(d) None of these
[42nd B.P.S.C. (Pre) 1997]
Ans. (d) None of these
- Diamond, graphite, and coal are all forms of carbon.
- Diamond has a relative density of 3.5, graphite is a black and shiny material with a relative density of 2.25, and coal is a solid form of carbon that is often used as fuel.
- All three of these substances contain carbon.
|
3. Arrange the following substances in chronological order of their first synthesis in the lab :
1. Black gold
2. Fullerene
3. Graphene
4. Kevlar
Select the correct answer from the codes given below :
Codes :
(a) 1 2 3 4
(b) 4 2 3 1
(c) 2 4 3 1
(d) 4 1 2 3
[U.P.P.C.S. (Pre) 2019]
Ans. (b) 4 2 3 1
- Kevlar is a strong and heat-resistant material created by Stephanie Kwolek at Dupont lab in the USA in 1965.
- Harold Kroto, Richard E. Smalley, James R. Heath and Robert F. Curl Jr. discovered Fullerene in 1985.
- Graphene, a form of carbon, was first made in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester.
- In 2019, scientists at the Tata Institute of Fundamental Research (TIFR) used gold nanoparticles and changed their size and space between them to create a new material called ‘black gold’, which can absorb light and carbon dioxide.
|
4. Which of the following is made up of Carbon only?
(a) Kevlar
(b) Lexan
(c) Graphene
(d) Spider silk
[U.P.P.C.S. (Mains) 2015]
Ans. (c) Graphene
- Graphene is a type of Carbon made up of one layer of atoms arranged in a hexagonal pattern.
- It is the building block of other Carbon forms such as Graphite, Charcoal, Carbon nanotubes, and Fullerenes.
- Graphene is essentially a tiny structure made of Carbon atoms.
|
5. Graphene is
(a) An alloy of carbon
(b) Nano structure of carbon
(c) Isotope of carbon
(d) None of the above
[U.P. P.C.S. (Pre) 2018]
Ans. (b) Nano structure of carbon
- Graphene is a type of Carbon that exists in a single layer of atoms in a 2D hexagonal pattern.
- Each atom forms a corner of the hexagon, making it a nanostructure.
- It’s the building block of other Carbon materials like Graphite, Charcoal, Carbon nanotubes, and Fullerenes.
- In other words, Graphene is a tiny Carbon structure.
|
6. Which of these is not an additional form of Carbon?
(a) Diamond
(b) Graphite
(c) Oxocarbon
(d) Fullerenes
[U.P.U.D.A./L.D.A. (Spl.) (Mains) 2010]
Ans. (c) Oxocarbon
- Oxocarbon is not an additional form (allotrope) of carbon.
- Oxocarbon is an inorganic compound consisting only of carbon and oxygen.
|
7. Pencil lead is :
(a) Graphite
(b) Charcoal
(c) Lamp black
(d) Coal
[Chhattisgarh P.C.S. (Pre) 2011, U.P.P.C.S. (Pre) 1994]
Ans. (a) Graphite
- Graphite and Diamond both are allotropes of Carbon.
- Pencil cores are made of Graphite mixed with a clay binder which leaves grey or black marks that can be easily erased.
|
8. Lead Pencil contains –
(a) Lead
(b) Lead oxide
(c) Graphite
(d) Lead sulphide
[U.P.P.C.S. (Mains) 2006,Uttarakhand U.D.A./L.D.A. (Pre) 2003]
Ans. (c) Graphite
- Carbon comes in different forms- Graphite and Diamond.
- Pencils contain Graphite and clay, which produces grey or black marks that can be easily wiped away.
|
9. The third allotrope of Carbon was discovered by three scientists, who were awarded the Nobel Prize for Chemistry. Find out who was not on that team–
(a) H.W. Kroto
(b) R.F. Curl
(c) R.E. Smalley
(d) Faimen
[U.P.P.C.S. (Pre) 2009]
Ans. (d) Faimen
- In 1996, Robert F. Curl, Sir Herald W. Kroto, and Richard E. Smalley won the Nobel Prize in Chemistry for finding Fullerenes, an arrangement of Carbon where molecules are packed together.
- This arrangement of Carbon has the molecular formula C60 and was named after the famous American architect and inventor, Richard Buckminster Fuller.
|
10. Which one of the following pairs is not correctly matched?
(a) Dry ice : Solid carbon dioxide
(b) Sevin : Insecticide
(c) Tef on : Polymer containing fluorine
(d) Fullerene : Organic compound containing fluorine
[U.P. P.C.S. (Mains) 2017]
Ans. (d) Fullerene : Organic compound containing fluorine
- Fullerene is a type of carbon.
- Buckminsterfullerene is a spheroid molecule made of 60 carbon atoms connected with single and double bonds, forming 12 pentagons and 20 hexagons, which looks like a soccer ball.
- It was named after the famous American architect Buckminster Fuller.
|
11. Buckminsterfullerene is –
(a) A form of carbon compound of clusters of 60 carbon atoms bond together in a polyhedral structure composed of pentagons or hexagons
(b) A polymer of fluorine
(c) An isotope of carbon heavier than C14
(d) None of these
[U.P.P.C.S. (Mains) 2010]
Ans. (a) A form of carbon compound of clusters of 60 carbon atoms bond together in a polyhedral structure composed of pentagons or hexagons
- Fullerene is a type of carbon.
- Buckminsterfullerene is a molecule made out of 60 carbon atoms that are connected by single and double bonds to make a hollow ball with 12 pentagons and 20 hexagons – which looks like a Soccer ball.
- It was named after the American Architect Fuller.
|
12. Which one of the following pairs is not correctly matched?
(a) Fullerene – Organic compounds containing fluorine
(b) Dry Ice – Solid carbon dioxide
(c) Keratin – Protein found in the outer layer of human skin
(d) Mustard gas – Poisonous liquid used is chemical warfare
[U.P.P.C.S. (Pre) 2001, 2003, U.P. Lower Sub. (Pre) 2003, U.P. Lower Sub. (Pre) 2002, U.P.U.D.A./L.D.A. (Pre) 2001]
Ans. (a) Fullerene – Organic compounds containing fluorine
- Dry Ice:
- Dry ice is just solid carbon dioxide (CO2).
- It is used for cooling.
- Mustard Gas:
- This dangerous chemical causes skin damage, eye irritation, lung problems, and can damage DNA.
- Symptoms usually appear 1-6 hours after exposure.
- Fullerene:
- Fullerene is an allotrope of carbon which has only carbon atoms.
- It is denoted by C60.
- Keratin:
- Keratin is a group of proteins that form a protective layer on the surface of skin cells.
- It helps protect the cells from harm.
|
13. Which one of the following pairs is not correctly matched?
(a) Dry ice : Solid carbon dioxide
(b) Mustard gas : Poisonous liquid used in chemical warfare
(c) Teflon : Polymer containing fluorine
(d) Fullerene : Organic compounds containing fluorine
[U.P.P.C.S. (Pre) 2006]
Ans. (d) Fullerene : Organic compounds containing fluorine
- Dry Ice:
- Dry ice is just solid carbon dioxide (CO2).
- It is used to keep things cool.
- Mustard gas:
- This is a deadly chemical that can harm your skin, eyes, lungs, and DNA.
- Its effects show up 1-6 hours after contact.
- Fullerene:
- This is an allotrope of carbon with all its atoms connected.
- It is also known as C60.
- Teflon:
- This is also called Polytetrafluoroethylene and was registered in 1944.
- It is a polymer that contains fluorine atoms.
|
14. Which one of the following pairs is incorrectly matched?
(a) Pyrene – Fire extinguisher
(b) Sulphur Dioxide – Acid rain
(c) Freon – Refrigerant
(d) Fullerene – Fluorine containing polymer
[U.P. P.C.S. (Mains) 2016]
Ans. (d) Fullerene – Fluorine containing polymer
- A Fullerene is a type of carbon that can be in the shape of a hollow sphere, ellipsoid, or tube, as well as many other shapes.
- The other answers are correct.
|
15. Which of the following does not contain carbon?
(a) Diamond
(b) Graphite
(c) Coal
(d) Sand
[U.P. Lower Sub. (Mains) 2013]
Ans. (d) Sand
- Carbon has the ability to exist in different forms, such as Diamond and Graphite.
- Coal is a sedimentary rock made mostly of Carbon, ranging from 40-90%.
- Sand is made of tiny pieces of rocks and minerals, but does not contain Carbon.
|
16. Which of these consists of carbon?
(a) Lignite
(b) Tin
(c) Silver
(d) Iron
[U.P.P.C.S. (Pre) 1993]
Ans. (a) Lignite
- Coal minerals are divided mainly into four types on the basis of the percentage of Carbon amount
| Lignite |
25-35% |
| Sub Bituminous |
35-45% |
| Bituminous |
45-85% |
| Anthracite |
more than 85%. |
|
17. Which one of the following types of coal contains a higher percentage of Carbon than the rest type of?
(a) Bituminous coal
(b) Lignite
(c) Peat
(d) Anthracite
[U.P.U.D.A./L.D.A. (Pre) 2001, I.A.S. (Pre) 1999]
Ans. (d) Anthracite
- Coal minerals are divided mainly into four types on the basis of the percentage of Carbon amount
| Lignite |
25-35% |
| Sub Bituminous |
35-45% |
| Bituminous |
45-85% |
| Anthracite |
more than 85%. |
|
18. The highest amount of Carbon is in –
(a) Pig Iron
(b) Wrought Iron
(c) Steel
(d) Alloy Steel
[U.P.P.C.S. (Mains) 2014]
Ans. (a) Pig Iron
- Pig Iron has a lot of Carbon, usually 3.5-4.5%.
- Wrought Iron is an Iron with almost no Carbon (less than 0.08%).
- Carbon steel is a type of steel with 0.2-1.5% Carbon.
- Alloy steel has 0.1-1% Carbon.
|
19. Which of the following is not in the form of a crystal?
(a) Diamond
(b) Quartz
(c) Sulphur
(d) Graphite
[M.P.P.C.S. (Pre) 1996]
Ans. (c) Sulphur
- Salt, Sugar, Diamond, Quartz, Ice, and Graphite all come in the form of crystals, but Sulphur does not.
- Sulphur is a type of chemical element that doesn’t contain metal.
|
20. Consider the following statements: Glass can be etched or scratched by –
1. Diamond
2. Hydrofluoric Acid
3. Aquaregia
4. Conc. Sulphuric Acid
Which of these statements are correct?
(a) 1 and 4
(b) 2 and 3
(c) 1 and 2
(d) 2 and 4
[I.A.S. (Pre) 1999]
Ans. (c) 1 and 2
- Diamonds are a very hard element used for grinding, cutting, drilling and polishing.
- They are also used as an abrasive, and small pieces of them are placed in grinding wheels, saw blades or drill bits.
- Diamonds are used to scratch glass, and hydrofluoric acid is one of the strongest acids used for industrial processes, such as etching glass, cleaning metal and making electronics.
|
21. For the ceiling of diamonds, the unit of weight is a carat. One carat is equal to –
(a) 100 mg
(b) 200 mg
(c) 300 mg
(d) 400 mg
[U.P.P.C.S. (Mains) 2013]
Ans. (b) 200 mg
- The carat is a unit for measuring the weight of gems and pearls, and is equal to 200 milligrams.
|
22. Graphene has been frequently in the news recently. What is its importance?
1. It is a two-dimensional material and has good electrical conductivity.
2. It is one of the thinnest but strongest materials tested so far.
3. It is entirely made of silicon and has high optical transparency.
4. It can be used as ‘conducting electrodes’ required for touchscreens, LCDs, and organic LEDs.
Which of the statement(s) given above is/are correct?
(a) 1 and 2
(b) 3 and 4
(c) 1, 2 and 4
(d) 1, 2, 3 and 4
[I.A.S. (Pre) 2012]
Ans. (c) 1, 2 and 4
- Graphene is an ultra-thin Carbon molecule that has amazing qualities.
- In 2004, Andre Geim and Kostya Novoselov from Manchester University discovered it.
- For this discovery, they were awarded the Nobel Prize in 2010.
- They extracted Graphene from a Graphite sample. Graphene has two dimensions, which makes it easier to control electricity compared to three-dimensional elements.
- It is very thin, yet the strongest material tested so far.
- It is also almost transparent, yet dense enough that even the smallest gas molecules can’t pass through it.
- Graphene is used in computer chips, communication devices and touchscreens as conducting electrodes.
|
23. Which one of the following materials is strongest?
(a) German Silver
(b) Brass
(c) Steel
(d) Graphene
[U.P.P.C.S. (Mains) 2015]
Ans. (d) Graphene
- Graphene is a single-atom thick form of Carbon, with amazing properties.
- Geim and Kostya Novoselov from Manchester University discovered it in 2004 and were rewarded with the Nobel Prize in 2010.
- Graphene was taken from a piece of Graphite.
- It is two-dimensional, which makes it easier to control electricity than three-dimensional elements.
- It is incredibly thin but also very strong, and is so dense that not even the smallest gas molecules can pass through it.
- It is used in computer chips, communication devices and touchscreens, and as the conducting electrode in devices like touchscreens, LCDs and organic LEDs.
|
24. Consider the following statements and select the correct answer from the codes given below –
(1) Water becomes harder due to the presence of Calcium Sulphate and it is not usable.
(2) Diamond is harder than copper and iron.
(3) Oxygen is the main component of air.
(4) Nitrogen is used in the manufacture of vegetable ghee.
Code :
(a) 1 and 2
(b) 3 and 4
(c) 1 and 3
(d) 2 and 4
[U.P.U.D.A./L.D.A. (Pre) 2001]
Ans. (a) 1 and 2
- Hard water has a lot of minerals in it, like Magnesium Sulphate or Calcium Sulphate, which don’t go away even if you heat it.
- Diamond is the strongest material.
- Air is about 78% Nitrogen.
- People sometimes use Vanaspati ghee instead of real ghee to save money, so only statements 1 and 2 are true.
|
25. Which lubricant is used for heavy machines?
(a) Bauxite
(b) Phosphorus
(c) Graphite
(d) Silicon oil
[R.A.S./R.T.S. (Pre) 1999]
Ans. (c) Graphite
- Graphite lubricant is a thin black substance that prevents things from sticking together and reduces friction.
- It is made of Carbon.
- It is used to make industrial and automotive machines run smoother.
|
26. Which of the following is also used as a lubricant?
(a) Cuprite
(b) Graphite
(c) Haematite
(d) Cryolite
[M.P.P.C.S. (Pre) 2017]
Ans. (b) Graphite
- Graphite is a type of carbon that is made up of crystals.
- It is often used as a lubricant because it has a soft texture.
- The carbon atoms in the crystal are arranged in a hexagon-like shape and the layers are held together by weak forces called Van der waals.
- This makes graphite soft and slippery.
|
27. Dry ice is –
(a) Solid water
(b) Mountain ice
(c) Solid CO2
(d) Solid carbon mono oxide
[Uttarakhand P.C.S. (Pre) 2002, 44th B.P.S.C. (Pre) 2000, 43rd B.P.S.C. (Pre) 1999, 42nd B.P.S.C. (Pre) 1998]
Ans. (c) Solid CO2
- Dry ice is another name for frozen carbon dioxide, sometimes called solid CO2 or dry snow.
|
28. Which one of the following is called ‘dry ice’?
(a) Dehydrated ice
(b) Solid hydrogen peroxide
(c) Solid water
(d) Solid carbon dioxide
[U.P.P.C.S. (Mains) 2014]
Ans. (d) Solid carbon dioxide
- Solid CO2 is known as dry ice.
|
29. Chemically Dry Ice is –
(a) Solid sulfur
(b) Ice made from distilled water
(c) Mixture of ice and common salt
(d) Solid carbon dioxide
[Uttarakhand U.D.A./L.D.A. (Mains) 2006, U.P.P.C.S. (Mains) 2009, Jharkhand P.C.S. (Pre) 2010]
Ans. (d) Solid carbon dioxide
- Dry ice is a type of solid made up of carbon dioxide (CO2), which is two oxygen atoms linked to one carbon atom.
|
30. ‘Dry Ice’ is –
(a) Frozen ice
(b) Frozen Carbon dioxide
(c) Frozen water
(d) Frozen oxygen
[Uttarakhand U.D.A./L.D.A. (Mains) 2006, R.A.S./R.T.S. (Pre) 2012]
Ans. (b) Frozen Carbon dioxide
- Dry ice is made of solid carbon dioxide, which is similar to regular ice.
- It is called dry ice because it skips the liquid phase and turns directly from solid to gas, a process called sublimation.
|
31. Water gas is
(a) CO + H2
(b) CO + H2O
(c) CO2+ H2 (d) CO2+ H2O
(e) None of these
[Chhattisgarh P.C.S. (Pre) 2016]
Ans. (a) CO + H2
- Water gas is a combination of carbon monoxide (CO) and hydrogen (H2).
- When the two are combined, methyl alcohol is created – this is the reaction of CO and H2 combining to form CH3OH.
|
32. The gas, which comes out on opening a soda water bottle, is :
(a) Carbon dioxide
(b) Hydrogen
(c) Nitrogen
(d) Sulfur dioxide
(e) None of the above/More than one of the above
[63rd B.P.S.C. (Pre) 2017]
Ans. (a) Carbon dioxide
- Soda water is regular water with carbon dioxide added to it, which makes it fizzy.
- When you open a bottle of soda water, gas (carbon dioxide) is released, creating bubbles in the drink.
|
33. What is the bond order of the CO group?
(a) 1
(b) 2.5
(c) 3.5
(d) 3
(e) None of the above/More than one of the above
[65th B.P.S.C. (Pre) 2019]
Ans. (d) 3
- Molecular orbital theory states that the bond order is calculated by subtracting the number of electrons in the antibonding orbitals from the number of electrons in the bonding orbitals and then dividing the result by two.
- Bond order = 1/2 [Nb-Na]
- Where, Nb= number of bonding electrons
- Na= number of antibonding electrons
- CO (Carbon monoxide) molecule has 10 valence electrons, four from the carbon atom (2s22p2) and six from the oxygen atom(2s2 2p4).
- According to the molecular orbital diagram, the molecular orbital configuration is given as here, Nb= 8; Na= 2
- Thus, Bond order of CO = 1/2[8 – 2] = 3
- Note: Here the calculations are done ignoring the 1s orbitals because there will be 2 electrons in the bonding and 2 in the antibonding.
|
