Molecules of which of the following has cage like structure ? 1. Diamond 2. Graphite 3. Fullerenes Select the correct answer using the code given below :
- A.1, 2 and 3
- B.2 and 3 only
- C.2 only
- D.3 only
Correct answer
Explanation
The correct answer is D, 3 only. Of the three forms of carbon, only fullerenes are made of closed, hollow, cage-like molecules.
The best-known fullerene is buckminsterfullerene, C60, a hollow sphere of 60 carbon atoms arranged in 20 hexagons and 12 pentagons, shaped like a football. It is named after the architect Buckminster Fuller, whose geodesic domes it resembles, and its discovery in 1985 won Kroto, Curl and Smalley the 1996 Nobel Prize in Chemistry. Diamond and graphite, by contrast, are giant covalent networks with no separate molecules at all.
A is wrong because diamond is a rigid three-dimensional network in which each carbon bonds to four others in a tetrahedron, the hardest natural substance, and it is no cage.
B is wrong because graphite is made of flat sheets of hexagonal rings stacked in layers, held by weak forces, which is why it is soft and slippery.
C is wrong for the same reason, and it leaves out fullerenes, the one cage-like form.
Exam tip: diamond, 3D tetrahedral network; graphite, layers; fullerene C60, football-shaped cage.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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